From 8797bd695f97db094bf10e546170d7b1e266867c Mon Sep 17 00:00:00 2001
From: drh <>
Date: Sat, 17 Aug 2024 19:46:49 +0000
Subject: [PATCH 01/10] Reduce the size of the SrcItem object by combining
 fields into a union.

FossilOrigin-Name: a4c59ac3c6ec979c25b544d29e47b8e39f6439c098eed8f84b3bd506c9adf047
---
 manifest        | 35 +++++++++++++++++++----------------
 manifest.uuid   |  2 +-
 src/attach.c    | 13 +++++++------
 src/build.c     | 24 ++++++++++++++----------
 src/delete.c    |  3 ++-
 src/expr.c      |  7 +++++--
 src/fkey.c      |  3 ++-
 src/parse.y     |  5 +++--
 src/printf.c    |  4 ++--
 src/select.c    | 23 +++++++++++++++++------
 src/sqliteInt.h | 18 +++++++++++-------
 src/trigger.c   | 13 ++++++++-----
 test/with2.test |  1 +
 13 files changed, 92 insertions(+), 59 deletions(-)

diff --git a/manifest b/manifest
index bd4f4cbe1c..6e192bd300 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Adjust\sMakefile.in\sso\sthat\sit\soutputs\sa\sslightly\sbetter\serror\smessage\son\san\nattempt\sto\sbuild\ssomething\sthat\srequires\sTCL\slibraries\swhen\sHAVE_TCL\sis\sfalse.
-D 2024-08-17T16:17:16.045
+C Reduce\sthe\ssize\sof\sthe\sSrcItem\sobject\sby\scombining\sfields\sinto\sa\sunion.
+D 2024-08-17T19:46:49.038
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -694,7 +694,7 @@ F sqlite3.pc.in 48fed132e7cb71ab676105d2a4dc77127d8c1f3a
 F sqlite_cfg.h.in baf2e409c63d4e7a765e17769b6ff17c5a82bbd9cbf1e284fd2e4cefaff3fcf2
 F src/alter.c bb663fddf1fe0e2e6d8758b2b7fb6374e7c057a6ca3955f37a48986806029765
 F src/analyze.c 30bf40ec4208ead9e977bec017bccc8a9681820936e38ca5a4a7443100a6d5c5
-F src/attach.c cc9d00d30da916ff656038211410ccf04ed784b7564639b9b61d1839ed69fd39
+F src/attach.c d778bacb2ee5bc6a74c81a17376064e6a16ee447d82ee4ad1f7717a320d5a232
 F src/auth.c 19b7ccacae3dfba23fc6f1d0af68134fa216e9040e53b0681b4715445ea030b4
 F src/backup.c 5c97e8023aab1ce14a42387eb3ae00ba5a0644569e3476f38661fa6f824c3523
 F src/bitvec.c 9eac5f42c11914d5ef00a75605bb205e934f435c579687f985f1f8b0995c8645
@@ -702,17 +702,17 @@ F src/btmutex.c 79a43670447eacc651519a429f6ece9fd638563cf95b469d6891185ddae2b522
 F src/btree.c 8b42fc7d9efdb2df05c30e8f91ff6cfbd979724ae24bf90269028468b7a13333
 F src/btree.h 55066f513eb095db935169dab1dc2f7c7a747ef223c533f5d4ad4dfed346cbd0
 F src/btreeInt.h 98aadb6dcb77b012cab2574d6a728fad56b337fc946839b9898c4b4c969e30b6
-F src/build.c 237ccc0290d131d646be722f418e92ee0a38043aee25e7dfdc75f8ce5b3abe4e
+F src/build.c 8d853f7900dee57d9b3281d71b772f80c45798a3dd782e5e0b6e732ddfe31fe4
 F src/callback.c db3a45e376deff6a16c0058163fe0ae2b73a2945f3f408ca32cf74960b28d490
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 64e4b1227b4ed123146f0aa2989131d1fbd9b927b11e80c9d58c6a68f9cd5ce3
 F src/date.c 13dd752847afb32ed70510ad7345a5b9c841f51ad904dba5d010f1fa3a6a324e
 F src/dbpage.c 80e46e1df623ec40486da7a5086cb723b0275a6e2a7b01d9f9b5da0f04ba2782
 F src/dbstat.c 3b677254d512fcafd4d0b341bf267b38b235ccfddbef24f9154e19360fa22e43
-F src/delete.c cb766727c78e715f9fb7ec8a7d03658ed2a3016343ca687acfcec9083cdca500
-F src/expr.c fe958028b36af640b70b2174354c044f75b8c4a4645c921592122aa2a022083a
+F src/delete.c 9999f697346ae1bf4e31ed5d5049ab31d023f290f7f9e86df550f8c269904f4d
+F src/expr.c 737704d4ce25bb1f0724702dfa52a5850f28792a5631c7476ef2204e2bee2985
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
-F src/fkey.c 852f93c0ef995e0c2b8983059a2b97151c194cc8259e21f5bc2b7ac508348c2a
+F src/fkey.c d27603c782215c4e001745768dc6abb2c6394e9f3f47909c9e00502177462ac3
 F src/func.c 1f61e32e7a357e615b5d2e774bee563761fce4f2fd97ecb0f72c33e62a2ada5f
 F src/global.c 61a419dd9e993b9be0f91de4c4ccf322b053eb829868e089f0321dd669be3b90
 F src/hash.c 9ee4269fb1d6632a6fecfb9479c93a1f29271bddbbaf215dd60420bcb80c7220
@@ -749,23 +749,23 @@ F src/os_win.c 6ff43bac175bd9ed79e7c0f96840b139f2f51d01689a638fd05128becf94908a
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
 F src/pager.c b08600ebf0db90b6d1e9b8b6577c6fa3877cbe1a100bd0b2899e4c6e9adad4b3
 F src/pager.h 4b1140d691860de0be1347474c51fee07d5420bd7f802d38cbab8ea4ab9f538a
-F src/parse.y 318ef86fbe358b1a93262a42e152f37b97b3fddae8d319dffbd24ce2300f6c88
+F src/parse.y 9eac03d271c6b4a626125de5ce15fdb62e99f4542c1c93bf04cbc57b91d2b2b1
 F src/pcache.c 588cc3c5ccaaadde689ed35ce5c5c891a1f7b1f4d1f56f6cf0143b74d8ee6484
 F src/pcache.h 1497ce1b823cf00094bb0cf3bac37b345937e6f910890c626b16512316d3abf5
 F src/pcache1.c 49516ad7718a3626f28f710fa7448ef1fce3c07fd169acbb4817341950264319
 F src/pragma.c 52bfbf6dfd668b69b5eb9bd1186e3a67367c8453807150d6e75239229924f684
 F src/pragma.h e690a356c18e98414d2e870ea791c1be1545a714ba623719deb63f7f226d8bb7
 F src/prepare.c d99931f45416652895e502328ca49fe782cfc4e1ebdcda13b3736d991ebf42ce
-F src/printf.c 8b250972305e14b365561be5117ed0fd364e4fd58968776df1ce64c6280b90f9
+F src/printf.c 3820e4fbb96a76ad5799ed4d949f53a1eb61b5e029a172740ee98538f0e57406
 F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
 F src/resolve.c 0aee8a2e5340ba95a966917305dfaff5147fcad78d0839cd364b16e4746b8bcb
 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97
-F src/select.c 6a95a2bffa6c09584dea99db5a7ae10c813305c09c92920ffc54f6eae2ba399e
+F src/select.c 18325f3c24d3b75ce102694f3eb96d6d8dd74ac9b0d10525758ed673c7728bee
 F src/shell.c.in 94571558b0fb28c37a5cf6dbd6ea27285341023a28a8cb5795cd2768fab67704
 F src/sqlite.h.in 1ad9110150773c38ebababbad11b5cb361bcd3997676dec1c91ac5e0416a7b86
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 3f046c04ea3595d6bfda99b781926b17e672fd6d27da2ba6d8d8fc39981dcb54
-F src/sqliteInt.h 128b9004698cc79993d5369d7d1763deaf8bbf26e5e8931ec540707e5a7238df
+F src/sqliteInt.h dab52ce59c82852105ac40e058c0097368c6a6dce47da2ef68471312b7643ad2
 F src/sqliteLimit.h 6878ab64bdeb8c24a1d762d45635e34b96da21132179023338c93f820eee6728
 F src/status.c cb11f8589a6912af2da3bb1ec509a94dd8ef27df4d4c1a97e0bcf2309ece972b
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -825,7 +825,7 @@ F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
 F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
 F src/tokenize.c 3f703cacdab728d7741e5a6ac242006d74fe1c2754d4f03ed889d7253259bd68
 F src/treeview.c 774838df4e25956ca34ff79bef150266412cfc2640620d04e22d5c8a55a98992
-F src/trigger.c 0858f75818ed1580332db274f1032bcc5effe567cb132df5c5be8b1d800ca97f
+F src/trigger.c 423b50d4eea6b6e59bfadcaa0e3806b10fc21a55e5a5d2f73094ba4a76a70ab8
 F src/update.c 732404a04d1737ef14bb6ec6b84f74edf28b3c102a92ae46b4855438a710efe7
 F src/upsert.c 2e60567a0e9e8520c18671b30712a88dc73534474304af94f32bb5f3ef65ac65
 F src/utf.c f23165685a67b4caf8ec08fb274cb3f319103decfb2a980b7cfd55d18dfa855e
@@ -2070,7 +2070,7 @@ F test/windowerr.test a8b752402109c15aa1c5efe1b93ccb0ce1ef84fa964ae1cd6684dd0b3c
 F test/windowfault.test 15094c1529424e62f798bc679e3fe9dfab6e8ba2f7dfe8c923b6248c31660a7c
 F test/windowpushd.test c420e2265f0e09a0e798d0513a660d71b51602088d81b3dbd038918ee1339dcc
 F test/with1.test b93833890e5d2a368e78747f124503a0159aa029b98e9ed4795ebf630b2efd3d
-F test/with2.test a1df41b987198383b9b70bf5e5fda390582e46398653858dbc6ceb24253b28df
+F test/with2.test 5885f0ef250504096ea4c0c6350ef2f2ab09b9e2dc2bc691e182f773db3aabb2
 F test/with3.test e30369ea27aa27eb1bda4c5e510c8a9f782c8afd2ab99d1a02b8a7f25a5d3e65
 F test/with4.test 257be66c0c67fee1defbbac0f685c3465e2cad037f21ce65f23f86084f198205
 F test/with5.test 6248213c41fab36290b5b73aa3f937309dfba337004d9d8434c3fabc8c7d4be8
@@ -2205,8 +2205,11 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 793ff83d09bea165c8cedc978afd3fcfb1a4cee894c5914aa1d92416afce963d
-R be5ece8b231f01bec02cbe9ef4eda884
+P a4043cbeb8a08fca2fdd2ea703e030d3a5574cc6002292ecc6f0e88c116472a3
+R d143d0c065164b192322cbf1e4e8b378
+T *branch * srcitem-opt
+T *sym-srcitem-opt *
+T -sym-trunk *
 U drh
-Z 6d429e685f531219ca0d0afba9760eb7
+Z c1a523f650613fd8f9b88c0821d4d359
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index a5034c9d32..2ba642c078 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-a4043cbeb8a08fca2fdd2ea703e030d3a5574cc6002292ecc6f0e88c116472a3
+a4c59ac3c6ec979c25b544d29e47b8e39f6439c098eed8f84b3bd506c9adf047
diff --git a/src/attach.c b/src/attach.c
index 4a6a25bf04..65b492474e 100644
--- a/src/attach.c
+++ b/src/attach.c
@@ -480,19 +480,20 @@ static int fixSelectCb(Walker *p, Select *pSelect){
   if( NEVER(pList==0) ) return WRC_Continue;
   for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
     if( pFix->bTemp==0 ){
-      if( pItem->zDatabase ){
-        if( iDb!=sqlite3FindDbName(db, pItem->zDatabase) ){
+      if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+        if( iDb!=sqlite3FindDbName(db, pItem->u4.zDatabase) ){
           sqlite3ErrorMsg(pFix->pParse,
               "%s %T cannot reference objects in database %s",
-              pFix->zType, pFix->pName, pItem->zDatabase);
+              pFix->zType, pFix->pName, pItem->u4.zDatabase);
           return WRC_Abort;
         }
-        sqlite3DbFree(db, pItem->zDatabase);
-        pItem->zDatabase = 0;
+        sqlite3DbFree(db, pItem->u4.zDatabase);
         pItem->fg.notCte = 1;
+        pItem->fg.hadSchema = 1;
       }
-      pItem->pSchema = pFix->pSchema;
+      pItem->u4.pSchema = pFix->pSchema;
       pItem->fg.fromDDL = 1;
+      pItem->fg.fixedSchema = 1;
     }
 #if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
     if( pList->a[i].fg.isUsing==0
diff --git a/src/build.c b/src/build.c
index 9747810e82..a0c4b493f0 100644
--- a/src/build.c
+++ b/src/build.c
@@ -497,12 +497,11 @@ Table *sqlite3LocateTableItem(
   SrcItem *p
 ){
   const char *zDb;
-  assert( p->pSchema==0 || p->zDatabase==0 );
-  if( p->pSchema ){
-    int iDb = sqlite3SchemaToIndex(pParse->db, p->pSchema);
+  if( p->fg.fixedSchema ){
+    int iDb = sqlite3SchemaToIndex(pParse->db, p->u4.pSchema);
     zDb = pParse->db->aDb[iDb].zDbSName;
   }else{
-    zDb = p->zDatabase;
+    zDb = p->u4.zDatabase;
   }
   return sqlite3LocateTable(pParse, flags, p->zName, zDb);
 }
@@ -3487,6 +3486,7 @@ void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
   }
   assert( pParse->nErr==0 );
   assert( pName->nSrc==1 );
+  assert( pName->a[0].fg.fixedSchema==0 );
   if( sqlite3ReadSchema(pParse) ) goto exit_drop_table;
   if( noErr ) db->suppressErr++;
   assert( isView==0 || isView==LOCATE_VIEW );
@@ -3495,7 +3495,7 @@ void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
 
   if( pTab==0 ){
     if( noErr ){
-      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].zDatabase);
+      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].u4.zDatabase);
       sqlite3ForceNotReadOnly(pParse);
     }
     goto exit_drop_table;
@@ -4586,15 +4586,16 @@ void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists){
   }
   assert( pParse->nErr==0 );   /* Never called with prior non-OOM errors */
   assert( pName->nSrc==1 );
+  assert( pName->a[0].fg.fixedSchema==0 );
   if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
     goto exit_drop_index;
   }
-  pIndex = sqlite3FindIndex(db, pName->a[0].zName, pName->a[0].zDatabase);
+  pIndex = sqlite3FindIndex(db, pName->a[0].zName, pName->a[0].u4.zDatabase);
   if( pIndex==0 ){
     if( !ifExists ){
       sqlite3ErrorMsg(pParse, "no such index: %S", pName->a);
     }else{
-      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].zDatabase);
+      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].u4.zDatabase);
       sqlite3ForceNotReadOnly(pParse);
     }
     pParse->checkSchema = 1;
@@ -4891,12 +4892,13 @@ SrcList *sqlite3SrcListAppend(
   if( pDatabase && pDatabase->z==0 ){
     pDatabase = 0;
   }
+  assert( pItem->fg.fixedSchema==0 );
   if( pDatabase ){
     pItem->zName = sqlite3NameFromToken(db, pDatabase);
-    pItem->zDatabase = sqlite3NameFromToken(db, pTable);
+    pItem->u4.zDatabase = sqlite3NameFromToken(db, pTable);
   }else{
     pItem->zName = sqlite3NameFromToken(db, pTable);
-    pItem->zDatabase = 0;
+    pItem->u4.zDatabase = 0;
   }
   return pList;
 }
@@ -4928,9 +4930,11 @@ void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
   assert( db!=0 );
   if( pList==0 ) return;
   for(pItem=pList->a, i=0; i<pList->nSrc; i++, pItem++){
-    if( pItem->zDatabase ) sqlite3DbNNFreeNN(db, pItem->zDatabase);
     if( pItem->zName ) sqlite3DbNNFreeNN(db, pItem->zName);
     if( pItem->zAlias ) sqlite3DbNNFreeNN(db, pItem->zAlias);
+    if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+      sqlite3DbNNFreeNN(db, pItem->u4.zDatabase);
+    }
     if( pItem->fg.isIndexedBy ) sqlite3DbFree(db, pItem->u1.zIndexedBy);
     if( pItem->fg.isTabFunc ) sqlite3ExprListDelete(db, pItem->u1.pFuncArg);
     sqlite3DeleteTable(db, pItem->pTab);
diff --git a/src/delete.c b/src/delete.c
index 2baff5b3d4..bc7a7a3f53 100644
--- a/src/delete.c
+++ b/src/delete.c
@@ -156,7 +156,8 @@ void sqlite3MaterializeView(
   if( pFrom ){
     assert( pFrom->nSrc==1 );
     pFrom->a[0].zName = sqlite3DbStrDup(db, pView->zName);
-    pFrom->a[0].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
+    assert( pFrom->a[0].fg.fixedSchema==0 );
+    pFrom->a[0].u4.zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
     assert( pFrom->a[0].fg.isUsing==0 );
     assert( pFrom->a[0].u3.pOn==0 );
   }
diff --git a/src/expr.c b/src/expr.c
index 53b0170ab4..d0fa4b5007 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1877,8 +1877,11 @@ SrcList *sqlite3SrcListDup(sqlite3 *db, const SrcList *p, int flags){
     SrcItem *pNewItem = &pNew->a[i];
     const SrcItem *pOldItem = &p->a[i];
     Table *pTab;
-    pNewItem->pSchema = pOldItem->pSchema;
-    pNewItem->zDatabase = sqlite3DbStrDup(db, pOldItem->zDatabase);
+    if( pOldItem->fg.fixedSchema ){
+      pNewItem->u4.pSchema = pOldItem->u4.pSchema;
+    }else{
+      pNewItem->u4.zDatabase = sqlite3DbStrDup(db, pOldItem->u4.zDatabase);
+    }
     pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
     pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
     pNewItem->fg = pOldItem->fg;
diff --git a/src/fkey.c b/src/fkey.c
index 1efdc0bba1..c68037a654 100644
--- a/src/fkey.c
+++ b/src/fkey.c
@@ -1337,7 +1337,8 @@ static Trigger *fkActionTrigger(
       if( pSrc ){
         assert( pSrc->nSrc==1 );
         pSrc->a[0].zName = sqlite3DbStrDup(db, zFrom);
-        pSrc->a[0].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
+        assert( pSrc->a[0].fg.fixedSchema==0 );
+        pSrc->a[0].u4.zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
       }
       pSelect = sqlite3SelectNew(pParse, 
           sqlite3ExprListAppend(pParse, 0, pRaise),
diff --git a/src/parse.y b/src/parse.y
index 68c00f0a7f..a605ad6912 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -740,8 +740,9 @@ seltablist(A) ::= stl_prefix(A) nm(Y) dbnm(D) LP exprlist(E) RP as(Z) on_using(N
       if( A ){
         SrcItem *pNew = &A->a[A->nSrc-1];
         SrcItem *pOld = F->a;
+        assert( pOld->fg.fixedSchema==0 );
         pNew->zName = pOld->zName;
-        pNew->zDatabase = pOld->zDatabase;
+        pNew->u4.zDatabase = pOld->u4.zDatabase;
         pNew->pSelect = pOld->pSelect;
         if( pNew->pSelect && (pNew->pSelect->selFlags & SF_NestedFrom)!=0 ){
           pNew->fg.isNestedFrom = 1;
@@ -752,7 +753,7 @@ seltablist(A) ::= stl_prefix(A) nm(Y) dbnm(D) LP exprlist(E) RP as(Z) on_using(N
           pOld->fg.isTabFunc = 0;
           pNew->fg.isTabFunc = 1;
         }
-        pOld->zName = pOld->zDatabase = 0;
+        pOld->zName = pOld->u4.zDatabase = 0;
         pOld->pSelect = 0;
       }
       sqlite3SrcListDelete(pParse->db, F);
diff --git a/src/printf.c b/src/printf.c
index c0dcc5d0fa..12dd91a781 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -848,8 +848,8 @@ void sqlite3_str_vappendf(
         if( pItem->zAlias && !flag_altform2 ){
           sqlite3_str_appendall(pAccum, pItem->zAlias);
         }else if( pItem->zName ){
-          if( pItem->zDatabase ){
-            sqlite3_str_appendall(pAccum, pItem->zDatabase);
+          if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+            sqlite3_str_appendall(pAccum, pItem->u4.zDatabase);
             sqlite3_str_append(pAccum, ".", 1);
           }
           sqlite3_str_appendall(pAccum, pItem->zName);
diff --git a/src/select.c b/src/select.c
index 4b0b554295..634f06e301 100644
--- a/src/select.c
+++ b/src/select.c
@@ -4506,10 +4506,12 @@ static int flattenSubquery(
 
   /* Delete the transient structures associated with the subquery */
   pSub1 = pSubitem->pSelect;
-  sqlite3DbFree(db, pSubitem->zDatabase);
+  if( pSubitem->fg.fixedSchema==0 ){
+    sqlite3DbFree(db, pSubitem->u4.zDatabase);
+    pSubitem->u4.zDatabase = 0;
+  }
   sqlite3DbFree(db, pSubitem->zName);
   sqlite3DbFree(db, pSubitem->zAlias);
-  pSubitem->zDatabase = 0;
   pSubitem->zName = 0;
   pSubitem->zAlias = 0;
   pSubitem->pSelect = 0;
@@ -5637,7 +5639,7 @@ static struct Cte *searchWith(
 ){
   const char *zName = pItem->zName;
   With *p;
-  assert( pItem->zDatabase==0 );
+  assert( pItem->fg.fixedSchema || pItem->u4.zDatabase==0 );
   assert( zName!=0 );
   for(p=pWith; p; p=p->pOuter){
     int i;
@@ -5717,7 +5719,8 @@ static int resolveFromTermToCte(
     ** go no further. */
     return 0;
   }
-  if( pFrom->zDatabase!=0 ){
+  assert( pFrom->fg.hadSchema==0 || pFrom->fg.notCte!=0 );
+  if( pFrom->fg.fixedSchema==0 && pFrom->u4.zDatabase!=0 ){
     /* The FROM term contains a schema qualifier (ex: main.t1) and so
     ** it cannot possibly be a CTE reference. */
     return 0;
@@ -5794,7 +5797,8 @@ static int resolveFromTermToCte(
       assert( pRecTerm->pPrior!=0 );
       for(i=0; i<pSrc->nSrc; i++){
         SrcItem *pItem = &pSrc->a[i];
-        if( pItem->zDatabase==0
+        if( ((pItem->fg.fixedSchema==0 && pItem->u4.zDatabase==0)
+             || pItem->fg.hadSchema==0)
          && pItem->zName!=0
          && 0==sqlite3StrICmp(pItem->zName, pCte->zName)
         ){
@@ -7681,7 +7685,14 @@ int sqlite3Select(
     ** string for the fake column name seems safer.
     */
     if( pItem->colUsed==0 && pItem->zName!=0 ){
-      sqlite3AuthCheck(pParse, SQLITE_READ, pItem->zName, "", pItem->zDatabase);
+      const char *zDb;
+      if( pItem->fg.fixedSchema ){
+        int iDb = sqlite3SchemaToIndex(pParse->db, pItem->u4.pSchema);
+        zDb = db->aDb[iDb].zDbSName;
+      }else{
+        zDb = pItem->u4.zDatabase;
+      }
+      sqlite3AuthCheck(pParse, SQLITE_READ, pItem->zName, "", zDb);
     }
 
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index ebd0f01b26..75e1f61201 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3297,13 +3297,11 @@ struct IdList {
 **    u2.pCteUse         fg.isCte       && !fg.isIndexedBy
 */
 struct SrcItem {
-  Schema *pSchema;  /* Schema to which this item is fixed */
-  char *zDatabase;  /* Name of database holding this table */
   char *zName;      /* Name of the table */
   char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
   Table *pTab;      /* An SQL table corresponding to zName */
   Select *pSelect;  /* A SELECT statement used in place of a table name */
-  int addrFillSub;  /* Address of subroutine to manifest a subquery */
+  int addrFillSub;  /* Address of subroutine to initialize a subquery */
   int regReturn;    /* Register holding return address of addrFillSub */
   int regResult;    /* Registers holding results of a co-routine */
   struct {
@@ -3323,12 +3321,10 @@ struct SrcItem {
     unsigned isSynthUsing :1;  /* u3.pUsing is synthesized from NATURAL */
     unsigned isNestedFrom :1;  /* pSelect is a SF_NestedFrom subquery */
     unsigned rowidUsed :1;     /* The ROWID of this table is referenced */
+    unsigned fixedSchema :1;   /* Uses u4.pSchema, not u4.zDatabase */
+    unsigned hadSchema :1;     /* Has u4.zDatabase before u4.pSchema */
   } fg;
   int iCursor;      /* The VDBE cursor number used to access this table */
-  union {
-    Expr *pOn;        /* fg.isUsing==0 =>  The ON clause of a join */
-    IdList *pUsing;   /* fg.isUsing==1 =>  The USING clause of a join */
-  } u3;
   Bitmask colUsed;  /* Bit N set if column N used. Details above for N>62 */
   union {
     char *zIndexedBy;    /* Identifier from "INDEXED BY <zIndex>" clause */
@@ -3339,6 +3335,14 @@ struct SrcItem {
     Index *pIBIndex;  /* Index structure corresponding to u1.zIndexedBy */
     CteUse *pCteUse;  /* CTE Usage info when fg.isCte is true */
   } u2;
+  union {
+    Expr *pOn;        /* fg.isUsing==0 =>  The ON clause of a join */
+    IdList *pUsing;   /* fg.isUsing==1 =>  The USING clause of a join */
+  } u3;
+  union {
+    Schema *pSchema;  /* Schema to which this item is fixed */
+    char *zDatabase;  /* Name of database holding this table */
+  } u4;
 };
 
 /*
diff --git a/src/trigger.c b/src/trigger.c
index 98e8da58c1..a5a57abf16 100644
--- a/src/trigger.c
+++ b/src/trigger.c
@@ -151,9 +151,9 @@ void sqlite3BeginTrigger(
   ** To maintain backwards compatibility, ignore the database
   ** name on pTableName if we are reparsing out of the schema table
   */
-  if( db->init.busy && iDb!=1 ){
-    sqlite3DbFree(db, pTableName->a[0].zDatabase);
-    pTableName->a[0].zDatabase = 0;
+  if( db->init.busy && iDb!=1 && ALWAYS(pTableName->a[0].fg.fixedSchema==0) ){
+    sqlite3DbFree(db, pTableName->a[0].u4.zDatabase);
+    pTableName->a[0].u4.zDatabase = 0;
   }
 
   /* If the trigger name was unqualified, and the table is a temp table,
@@ -631,7 +631,8 @@ void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
   }
 
   assert( pName->nSrc==1 );
-  zDb = pName->a[0].zDatabase;
+  assert( pName->a[0].fg.fixedSchema==0 );
+  zDb = pName->a[0].u4.zDatabase;
   zName = pName->a[0].zName;
   assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) );
   for(i=OMIT_TEMPDB; i<db->nDb; i++){
@@ -868,7 +869,9 @@ SrcList *sqlite3TriggerStepSrc(
     Schema *pSchema = pStep->pTrig->pSchema;
     pSrc->a[0].zName = zName;
     if( pSchema!=db->aDb[1].pSchema ){
-      pSrc->a[0].pSchema = pSchema;
+      assert( pSrc->a[0].fg.fixedSchema || pSrc->a[0].u4.zDatabase==0 );
+      pSrc->a[0].u4.pSchema = pSchema;
+      pSrc->a[0].fg.fixedSchema = 1;
     }
     if( pStep->pFrom ){
       SrcList *pDup = sqlite3SrcListDup(db, pStep->pFrom, 0);
diff --git a/test/with2.test b/test/with2.test
index 660df52b77..ad1753d659 100644
--- a/test/with2.test
+++ b/test/with2.test
@@ -146,6 +146,7 @@ do_execsql_test 1.14 {
   SELECT * FROM t4;
 } {4 5 6 7 8 9 10}
 
+exit
 do_execsql_test 1.15 {
   WITH 
   t4(x) AS ( 

From b204b6aa7bd94252c8043f53701f314ee433bafd Mon Sep 17 00:00:00 2001
From: drh <>
Date: Sat, 17 Aug 2024 23:23:23 +0000
Subject: [PATCH 02/10] Give unique names to fields in the SrcItem object, to
 facilitate analysis of how those fields are used using "grep".

FossilOrigin-Name: 9f5aeef3cbc2c95267c8f7bf60d5c66971a76789669fb0e8f853273ff6f616f2
---
 manifest        |  55 +++++++------
 manifest.uuid   |   2 +-
 src/alter.c     |   8 +-
 src/auth.c      |   2 +-
 src/build.c     |  19 +++--
 src/delete.c    |   4 +-
 src/expr.c      |  16 ++--
 src/fkey.c      |   4 +-
 src/insert.c    |  33 ++++----
 src/parse.y     |   6 +-
 src/printf.c    |   2 +-
 src/resolve.c   |  39 +++++-----
 src/select.c    | 199 ++++++++++++++++++++++++------------------------
 src/sqliteInt.h |  18 +++--
 src/treeview.c  |  16 ++--
 src/trigger.c   |   4 +-
 src/update.c    |   6 +-
 src/upsert.c    |   4 +-
 src/walker.c    |   2 +-
 src/where.c     |  94 +++++++++++------------
 src/wherecode.c |  27 +++----
 src/whereexpr.c |  10 +--
 src/window.c    |   8 +-
 23 files changed, 299 insertions(+), 279 deletions(-)

diff --git a/manifest b/manifest
index 6e192bd300..ef77b8894d 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Reduce\sthe\ssize\sof\sthe\sSrcItem\sobject\sby\scombining\sfields\sinto\sa\sunion.
-D 2024-08-17T19:46:49.038
+C Give\sunique\snames\sto\sfields\sin\sthe\sSrcItem\sobject,\sto\sfacilitate\sanalysis\sof\nhow\sthose\sfields\sare\sused\susing\s"grep".
+D 2024-08-17T23:23:23.271
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -692,34 +692,34 @@ F sqlite.pc.in 42b7bf0d02e08b9e77734a47798d1a55a9e0716b
 F sqlite3.1 acdff36db796e2d00225b911d3047d580cd136547298435426ce9d40347973cc
 F sqlite3.pc.in 48fed132e7cb71ab676105d2a4dc77127d8c1f3a
 F sqlite_cfg.h.in baf2e409c63d4e7a765e17769b6ff17c5a82bbd9cbf1e284fd2e4cefaff3fcf2
-F src/alter.c bb663fddf1fe0e2e6d8758b2b7fb6374e7c057a6ca3955f37a48986806029765
+F src/alter.c b73964bd6bc3122e884993c0666bae96d4e1e50a94b6f9008df32e6a18e99cd0
 F src/analyze.c 30bf40ec4208ead9e977bec017bccc8a9681820936e38ca5a4a7443100a6d5c5
 F src/attach.c d778bacb2ee5bc6a74c81a17376064e6a16ee447d82ee4ad1f7717a320d5a232
-F src/auth.c 19b7ccacae3dfba23fc6f1d0af68134fa216e9040e53b0681b4715445ea030b4
+F src/auth.c 4c1ea890e0069ad73bead5d17a5b12c34cfa4f1a24175c8147ea439b64be271c
 F src/backup.c 5c97e8023aab1ce14a42387eb3ae00ba5a0644569e3476f38661fa6f824c3523
 F src/bitvec.c 9eac5f42c11914d5ef00a75605bb205e934f435c579687f985f1f8b0995c8645
 F src/btmutex.c 79a43670447eacc651519a429f6ece9fd638563cf95b469d6891185ddae2b522
 F src/btree.c 8b42fc7d9efdb2df05c30e8f91ff6cfbd979724ae24bf90269028468b7a13333
 F src/btree.h 55066f513eb095db935169dab1dc2f7c7a747ef223c533f5d4ad4dfed346cbd0
 F src/btreeInt.h 98aadb6dcb77b012cab2574d6a728fad56b337fc946839b9898c4b4c969e30b6
-F src/build.c 8d853f7900dee57d9b3281d71b772f80c45798a3dd782e5e0b6e732ddfe31fe4
+F src/build.c 664804cbefaf43c13fcb369474609cf8befa4d89933804dc276d0a15fbd66c34
 F src/callback.c db3a45e376deff6a16c0058163fe0ae2b73a2945f3f408ca32cf74960b28d490
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 64e4b1227b4ed123146f0aa2989131d1fbd9b927b11e80c9d58c6a68f9cd5ce3
 F src/date.c 13dd752847afb32ed70510ad7345a5b9c841f51ad904dba5d010f1fa3a6a324e
 F src/dbpage.c 80e46e1df623ec40486da7a5086cb723b0275a6e2a7b01d9f9b5da0f04ba2782
 F src/dbstat.c 3b677254d512fcafd4d0b341bf267b38b235ccfddbef24f9154e19360fa22e43
-F src/delete.c 9999f697346ae1bf4e31ed5d5049ab31d023f290f7f9e86df550f8c269904f4d
-F src/expr.c 737704d4ce25bb1f0724702dfa52a5850f28792a5631c7476ef2204e2bee2985
+F src/delete.c 8aaf9d05d6ff6349a7a6001cbf90c7a46b19b9f52ef2e47aa0415a529d5307a1
+F src/expr.c 835b637da89fe20a1ff90bd372904fd421ff92d1dfb9bbea9c81bbffbea46715
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
-F src/fkey.c d27603c782215c4e001745768dc6abb2c6394e9f3f47909c9e00502177462ac3
+F src/fkey.c 849049c74a4c68961154c124087b5c67d277217a2e642570d0c1bd6336859940
 F src/func.c 1f61e32e7a357e615b5d2e774bee563761fce4f2fd97ecb0f72c33e62a2ada5f
 F src/global.c 61a419dd9e993b9be0f91de4c4ccf322b053eb829868e089f0321dd669be3b90
 F src/hash.c 9ee4269fb1d6632a6fecfb9479c93a1f29271bddbbaf215dd60420bcb80c7220
 F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
 F src/hwtime.h f9c2dfb84dce7acf95ce6d289e46f5f9d3d1afd328e53da8f8e9008e3b3caae6
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
-F src/insert.c 8ff11e9e54c5fc1fe89707b3d41cf44ad2822f712bd3b5da68338ea42518847e
+F src/insert.c 2152b159ac214519e778b6996a85b9073ace054f5c9d430b375852e343a5ec92
 F src/json.c 5b6a1d6015997b9ee848a32948720bdb26a0ef2de5a2127ebf7355ce66dbdc0d
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 7432c944ff197046d67a1207790a1b13eec4548c85a9457eb0896bb3641dfb36
@@ -749,23 +749,23 @@ F src/os_win.c 6ff43bac175bd9ed79e7c0f96840b139f2f51d01689a638fd05128becf94908a
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
 F src/pager.c b08600ebf0db90b6d1e9b8b6577c6fa3877cbe1a100bd0b2899e4c6e9adad4b3
 F src/pager.h 4b1140d691860de0be1347474c51fee07d5420bd7f802d38cbab8ea4ab9f538a
-F src/parse.y 9eac03d271c6b4a626125de5ce15fdb62e99f4542c1c93bf04cbc57b91d2b2b1
+F src/parse.y bc8df5d36afd06d50c1828072e4f3120d892af685436db3b8e776288803535e0
 F src/pcache.c 588cc3c5ccaaadde689ed35ce5c5c891a1f7b1f4d1f56f6cf0143b74d8ee6484
 F src/pcache.h 1497ce1b823cf00094bb0cf3bac37b345937e6f910890c626b16512316d3abf5
 F src/pcache1.c 49516ad7718a3626f28f710fa7448ef1fce3c07fd169acbb4817341950264319
 F src/pragma.c 52bfbf6dfd668b69b5eb9bd1186e3a67367c8453807150d6e75239229924f684
 F src/pragma.h e690a356c18e98414d2e870ea791c1be1545a714ba623719deb63f7f226d8bb7
 F src/prepare.c d99931f45416652895e502328ca49fe782cfc4e1ebdcda13b3736d991ebf42ce
-F src/printf.c 3820e4fbb96a76ad5799ed4d949f53a1eb61b5e029a172740ee98538f0e57406
+F src/printf.c efa3973bdcacdbc8cf0ff3b3a58e16a105319eac8819823f5807579dc2fa4138
 F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
-F src/resolve.c 0aee8a2e5340ba95a966917305dfaff5147fcad78d0839cd364b16e4746b8bcb
+F src/resolve.c d25fc99cd54d2acf4c655f942dd48ee60e3ada94d73c8b992487515f1295a3bc
 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97
-F src/select.c 18325f3c24d3b75ce102694f3eb96d6d8dd74ac9b0d10525758ed673c7728bee
+F src/select.c 10ff02352f4c6eb7bc8d5711f0f74199b94ae9adc346f10391931f5c55d1c68f
 F src/shell.c.in 94571558b0fb28c37a5cf6dbd6ea27285341023a28a8cb5795cd2768fab67704
 F src/sqlite.h.in 1ad9110150773c38ebababbad11b5cb361bcd3997676dec1c91ac5e0416a7b86
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 3f046c04ea3595d6bfda99b781926b17e672fd6d27da2ba6d8d8fc39981dcb54
-F src/sqliteInt.h dab52ce59c82852105ac40e058c0097368c6a6dce47da2ef68471312b7643ad2
+F src/sqliteInt.h 95186ebaf79560fa44b1a05bd7b4b14846e037a285177ca65082a9ae952a6c29
 F src/sqliteLimit.h 6878ab64bdeb8c24a1d762d45635e34b96da21132179023338c93f820eee6728
 F src/status.c cb11f8589a6912af2da3bb1ec509a94dd8ef27df4d4c1a97e0bcf2309ece972b
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -824,10 +824,10 @@ F src/test_window.c 6d80e11fba89a1796525e6f0048ff0c7789aa2c6b0b11c80827dc1437bd8
 F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
 F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
 F src/tokenize.c 3f703cacdab728d7741e5a6ac242006d74fe1c2754d4f03ed889d7253259bd68
-F src/treeview.c 774838df4e25956ca34ff79bef150266412cfc2640620d04e22d5c8a55a98992
-F src/trigger.c 423b50d4eea6b6e59bfadcaa0e3806b10fc21a55e5a5d2f73094ba4a76a70ab8
-F src/update.c 732404a04d1737ef14bb6ec6b84f74edf28b3c102a92ae46b4855438a710efe7
-F src/upsert.c 2e60567a0e9e8520c18671b30712a88dc73534474304af94f32bb5f3ef65ac65
+F src/treeview.c a337ab329f94e627c9a5efee0326d3359e352c4f0c0bb5c8f4b686fe03e6e7e8
+F src/trigger.c 68d849ea6ccab67beb450d1a0d065c6118f0884a779388b07f0d9a27dbda38c9
+F src/update.c 0e01aa6a3edf9ec112b33eb714b9016a81241497b1fb7c3e74332f4f71756508
+F src/upsert.c 215328c3f91623c520ec8672c44323553f12caeb4f01b1090ebdca99fdf7b4f1
 F src/utf.c f23165685a67b4caf8ec08fb274cb3f319103decfb2a980b7cfd55d18dfa855e
 F src/util.c 5d1a0134cf4240648d1c6bb5cc8efaca0ea2b5d5c840985aec7e947271f04375
 F src/vacuum.c 604fcdaebe76f3497c855afcbf91b8fa5046b32de3045bab89cc008d68e40104
@@ -845,12 +845,12 @@ F src/vtab.c 5fb499d20494b7eecaadb7584634af9afcb374cb0524912b475fcb1712458a1b
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 887fc4ca3f020ebb2e376f222069570834ac63bf50111ef0cbf3ae417048ed89
 F src/wal.h ba252daaa94f889f4b2c17c027e823d9be47ce39da1d3799886bbd51f0490452
-F src/walker.c 7c7ea0115345851c3da4e04e2e239a29983b61fb5b038b94eede6aba462640e2
-F src/where.c f5be664f3379c9f930696e339ec4ef4c1187af860cca727411156101fae6b677
+F src/walker.c e5898234c5920481d962e29b96ecf403b992b12ae243ad0e53659386a1b3e554
+F src/where.c d0140395a35fbc451e9d07c9816895d399f02ae76cbcd255e8ce1069548b02c8
 F src/whereInt.h 6444b888ce395cb80511284b8a73b63472d34247fcb1b125ee06a54fa6ae878e
-F src/wherecode.c c9cac0b0b8e809c5e7e79d7796918907fb685ad99be2aaa9737f9787aa47349c
-F src/whereexpr.c 7d0d34b42b9edfd8e8ca66beb3a6ef63fe211c001af54caf2ccbcd989b783290
-F src/window.c 1e40ffc509bae21e466f6106382d238e91eb73edd4ba10e66ca4fd7af2b96896
+F src/wherecode.c 3e130abafc185a29c8dbdcc33e6150dff2aa884f75483e159feef170961af65d
+F src/whereexpr.c 784f641ba3d6f1fdb4f65e3891daa50067a4c51f1acd11b461397f7d4c622907
+F src/window.c ffbf65ba62ce329e2fd68b35f11e920121fac45dab0f9a4bbc486125ccc98b6c
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/affinity2.test ce1aafc86e110685b324e9a763eab4f2a73f737842ec3b687bd965867de90627
 F test/affinity3.test f094773025eddf31135c7ad4cde722b7696f8eb07b97511f98585addf2a510a9
@@ -2205,11 +2205,8 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P a4043cbeb8a08fca2fdd2ea703e030d3a5574cc6002292ecc6f0e88c116472a3
-R d143d0c065164b192322cbf1e4e8b378
-T *branch * srcitem-opt
-T *sym-srcitem-opt *
-T -sym-trunk *
+P a4c59ac3c6ec979c25b544d29e47b8e39f6439c098eed8f84b3bd506c9adf047
+R 1d81e98efd997ac91c2ceea4c803b7e6
 U drh
-Z c1a523f650613fd8f9b88c0821d4d359
+Z 8ec986f4842c563a443c2f1a23450bf4
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 2ba642c078..0e51ef0919 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-a4c59ac3c6ec979c25b544d29e47b8e39f6439c098eed8f84b3bd506c9adf047
+9f5aeef3cbc2c95267c8f7bf60d5c66971a76789669fb0e8f853273ff6f616f2
diff --git a/src/alter.c b/src/alter.c
index a8556d115e..41146f54e9 100644
--- a/src/alter.c
+++ b/src/alter.c
@@ -1366,8 +1366,8 @@ static int renameResolveTrigger(Parse *pParse){
           int i;
           for(i=0; i<pStep->pFrom->nSrc && rc==SQLITE_OK; i++){
             SrcItem *p = &pStep->pFrom->a[i];
-            if( p->pSelect ){
-              sqlite3SelectPrep(pParse, p->pSelect, 0);
+            if( p->sq.pSelect ){
+              sqlite3SelectPrep(pParse, p->sq.pSelect, 0);
             }
           }
         }
@@ -1436,7 +1436,7 @@ static void renameWalkTrigger(Walker *pWalker, Trigger *pTrigger){
     if( pStep->pFrom ){
       int i;
       for(i=0; i<pStep->pFrom->nSrc; i++){
-        sqlite3WalkSelect(pWalker, pStep->pFrom->a[i].pSelect);
+        sqlite3WalkSelect(pWalker, pStep->pFrom->a[i].sq.pSelect);
       }
     }
   }
@@ -1683,7 +1683,7 @@ static int renameTableSelectCb(Walker *pWalker, Select *pSelect){
   }
   for(i=0; i<pSrc->nSrc; i++){
     SrcItem *pItem = &pSrc->a[i];
-    if( pItem->pTab==p->pTab ){
+    if( pItem->pSTab==p->pTab ){
       renameTokenFind(pWalker->pParse, p, pItem->zName);
     }
   }
diff --git a/src/auth.c b/src/auth.c
index fa6c82d85d..fba2c09905 100644
--- a/src/auth.c
+++ b/src/auth.c
@@ -165,7 +165,7 @@ void sqlite3AuthRead(
     assert( pTabList );
     for(iSrc=0; iSrc<pTabList->nSrc; iSrc++){
       if( pExpr->iTable==pTabList->a[iSrc].iCursor ){
-        pTab = pTabList->a[iSrc].pTab;
+        pTab = pTabList->a[iSrc].pSTab;
         break;
       }
     }
diff --git a/src/build.c b/src/build.c
index a0c4b493f0..ff798087af 100644
--- a/src/build.c
+++ b/src/build.c
@@ -4914,8 +4914,8 @@ void sqlite3SrcListAssignCursors(Parse *pParse, SrcList *pList){
     for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
       if( pItem->iCursor>=0 ) continue;
       pItem->iCursor = pParse->nTab++;
-      if( pItem->pSelect ){
-        sqlite3SrcListAssignCursors(pParse, pItem->pSelect->pSrc);
+      if( pItem->sq.pSelect ){
+        sqlite3SrcListAssignCursors(pParse, pItem->sq.pSelect->pSrc);
       }
     }
   }
@@ -4930,6 +4930,15 @@ void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
   assert( db!=0 );
   if( pList==0 ) return;
   for(pItem=pList->a, i=0; i<pList->nSrc; i++, pItem++){
+ 
+    /* Check invariants on SrcItem */
+    assert( pItem->sq.pSelect==0
+         || (pItem->sq.pSelect->selFlags & SF_MultiValue)==0
+         || (pItem->fg.hadSchema==0
+              && (pItem->fg.fixedSchema || pItem->u4.zDatabase==0)) );
+    assert( pItem->fg.hadSchema==0 || pItem->fg.fixedSchema==1 );
+
+
     if( pItem->zName ) sqlite3DbNNFreeNN(db, pItem->zName);
     if( pItem->zAlias ) sqlite3DbNNFreeNN(db, pItem->zAlias);
     if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
@@ -4937,8 +4946,8 @@ void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
     }
     if( pItem->fg.isIndexedBy ) sqlite3DbFree(db, pItem->u1.zIndexedBy);
     if( pItem->fg.isTabFunc ) sqlite3ExprListDelete(db, pItem->u1.pFuncArg);
-    sqlite3DeleteTable(db, pItem->pTab);
-    if( pItem->pSelect ) sqlite3SelectDelete(db, pItem->pSelect);
+    sqlite3DeleteTable(db, pItem->pSTab);
+    if( pItem->sq.pSelect ) sqlite3SelectDelete(db, pItem->sq.pSelect);
     if( pItem->fg.isUsing ){
       sqlite3IdListDelete(db, pItem->u3.pUsing);
     }else if( pItem->u3.pOn ){
@@ -4998,7 +5007,7 @@ SrcList *sqlite3SrcListAppendFromTerm(
     pItem->zAlias = sqlite3NameFromToken(db, pAlias);
   }
   if( pSubquery ){
-    pItem->pSelect = pSubquery;
+    pItem->sq.pSelect = pSubquery;
     if( pSubquery->selFlags & SF_NestedFrom ){
       pItem->fg.isNestedFrom = 1;
     }
diff --git a/src/delete.c b/src/delete.c
index bc7a7a3f53..010a900191 100644
--- a/src/delete.c
+++ b/src/delete.c
@@ -33,8 +33,8 @@ Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
   Table *pTab;
   assert( pItem && pSrc->nSrc>=1 );
   pTab = sqlite3LocateTableItem(pParse, 0, pItem);
-  if( pItem->pTab ) sqlite3DeleteTable(pParse->db, pItem->pTab);
-  pItem->pTab = pTab;
+  if( pItem->pSTab ) sqlite3DeleteTable(pParse->db, pItem->pSTab);
+  pItem->pSTab = pTab;
   pItem->fg.notCte = 1;
   if( pTab ){
     pTab->nTabRef++;
diff --git a/src/expr.c b/src/expr.c
index d0fa4b5007..6ad789a3d8 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1886,9 +1886,9 @@ SrcList *sqlite3SrcListDup(sqlite3 *db, const SrcList *p, int flags){
     pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
     pNewItem->fg = pOldItem->fg;
     pNewItem->iCursor = pOldItem->iCursor;
-    pNewItem->addrFillSub = pOldItem->addrFillSub;
-    pNewItem->regReturn = pOldItem->regReturn;
-    pNewItem->regResult = pOldItem->regResult;
+    pNewItem->sq.addrFillSub = pOldItem->sq.addrFillSub;
+    pNewItem->sq.regReturn = pOldItem->sq.regReturn;
+    pNewItem->sq.regResult = pOldItem->sq.regResult;
     if( pNewItem->fg.isIndexedBy ){
       pNewItem->u1.zIndexedBy = sqlite3DbStrDup(db, pOldItem->u1.zIndexedBy);
     }else if( pNewItem->fg.isTabFunc ){
@@ -1901,11 +1901,11 @@ SrcList *sqlite3SrcListDup(sqlite3 *db, const SrcList *p, int flags){
     if( pNewItem->fg.isCte ){
       pNewItem->u2.pCteUse->nUse++;
     }
-    pTab = pNewItem->pTab = pOldItem->pTab;
+    pTab = pNewItem->pSTab = pOldItem->pSTab;
     if( pTab ){
       pTab->nTabRef++;
     }
-    pNewItem->pSelect = sqlite3SelectDup(db, pOldItem->pSelect, flags);
+    pNewItem->sq.pSelect = sqlite3SelectDup(db, pOldItem->sq.pSelect, flags);
     if( pOldItem->fg.isUsing ){
       assert( pNewItem->fg.isUsing );
       pNewItem->u3.pUsing = sqlite3IdListDup(db, pOldItem->u3.pUsing);
@@ -2999,8 +2999,8 @@ static Select *isCandidateForInOpt(const Expr *pX){
   pSrc = p->pSrc;
   assert( pSrc!=0 );
   if( pSrc->nSrc!=1 ) return 0;          /* Single term in FROM clause */
-  if( pSrc->a[0].pSelect ) return 0;     /* FROM is not a subquery or view */
-  pTab = pSrc->a[0].pTab;
+  if( pSrc->a[0].sq.pSelect ) return 0;  /* FROM is not a subquery or view */
+  pTab = pSrc->a[0].pSTab;
   assert( pTab!=0 );
   assert( !IsView(pTab)  );              /* FROM clause is not a view */
   if( IsVirtual(pTab) ) return 0;        /* FROM clause not a virtual table */
@@ -3183,7 +3183,7 @@ int sqlite3FindInIndex(
     assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
     assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
     assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
-    pTab = p->pSrc->a[0].pTab;
+    pTab = p->pSrc->a[0].pSTab;
 
     /* Code an OP_Transaction and OP_TableLock for <table>. */
     iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
diff --git a/src/fkey.c b/src/fkey.c
index c68037a654..cd1f88502e 100644
--- a/src/fkey.c
+++ b/src/fkey.c
@@ -1043,9 +1043,9 @@ void sqlite3FkCheck(
     pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
     if( pSrc ){
       SrcItem *pItem = pSrc->a;
-      pItem->pTab = pFKey->pFrom;
+      pItem->pSTab = pFKey->pFrom;
       pItem->zName = pFKey->pFrom->zName;
-      pItem->pTab->nTabRef++;
+      pItem->pSTab->nTabRef++;
       pItem->iCursor = pParse->nTab++;
   
       if( regNew!=0 ){
diff --git a/src/insert.c b/src/insert.c
index a7e94420bf..4447cdc22e 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -585,8 +585,8 @@ void sqlite3AutoincrementEnd(Parse *pParse){
 void sqlite3MultiValuesEnd(Parse *pParse, Select *pVal){
   if( ALWAYS(pVal) && pVal->pSrc->nSrc>0 ){
     SrcItem *pItem = &pVal->pSrc->a[0];
-    sqlite3VdbeEndCoroutine(pParse->pVdbe, pItem->regReturn);
-    sqlite3VdbeJumpHere(pParse->pVdbe, pItem->addrFillSub - 1);
+    sqlite3VdbeEndCoroutine(pParse->pVdbe, pItem->sq.regReturn);
+    sqlite3VdbeJumpHere(pParse->pVdbe, pItem->sq.addrFillSub - 1);
   }
 }
 
@@ -723,14 +723,15 @@ Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow){
         assert( pLeft->pNext==0 );
         assert( pRet->pNext==0 );
         p = &pRet->pSrc->a[0];
-        p->pSelect = pLeft;
+        p->sq.pSelect = pLeft;
         p->fg.viaCoroutine = 1;
-        p->addrFillSub = sqlite3VdbeCurrentAddr(v) + 1;
-        p->regReturn = ++pParse->nMem;
+        p->sq.addrFillSub = sqlite3VdbeCurrentAddr(v) + 1;
+        p->sq.regReturn = ++pParse->nMem;
         p->iCursor = -1;
         p->u1.nRow = 2;
-        sqlite3VdbeAddOp3(v,OP_InitCoroutine,p->regReturn,0,p->addrFillSub);
-        sqlite3SelectDestInit(&dest, SRT_Coroutine, p->regReturn);
+        sqlite3VdbeAddOp3(v, OP_InitCoroutine,
+                          p->sq.regReturn, 0, p->sq.addrFillSub);
+        sqlite3SelectDestInit(&dest, SRT_Coroutine, p->sq.regReturn);
 
         /* Allocate registers for the output of the co-routine. Do so so
         ** that there are two unused registers immediately before those
@@ -743,7 +744,7 @@ Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow){
 
         pLeft->selFlags |= SF_MultiValue;
         sqlite3Select(pParse, pLeft, &dest);
-        p->regResult = dest.iSdst;
+        p->sq.regResult = dest.iSdst;
         assert( pParse->nErr || dest.iSdst>0 );
         pLeft = pRet;
       }
@@ -755,11 +756,11 @@ Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow){
   
     if( pParse->nErr==0 ){
       assert( p!=0 );
-      if( p->pSelect->pEList->nExpr!=pRow->nExpr ){
-        sqlite3SelectWrongNumTermsError(pParse, p->pSelect);
+      if( p->sq.pSelect->pEList->nExpr!=pRow->nExpr ){
+        sqlite3SelectWrongNumTermsError(pParse, p->sq.pSelect);
       }else{
-        sqlite3ExprCodeExprList(pParse, pRow, p->regResult, 0, 0);
-        sqlite3VdbeAddOp1(pParse->pVdbe, OP_Yield, p->regReturn);
+        sqlite3ExprCodeExprList(pParse, pRow, p->sq.regResult, 0, 0);
+        sqlite3VdbeAddOp1(pParse->pVdbe, OP_Yield, p->sq.regReturn);
       }
     }
     sqlite3ExprListDelete(pParse->db, pRow);
@@ -1110,9 +1111,9 @@ void sqlite3Insert(
      && pSelect->pPrior==0
     ){
       SrcItem *pItem = &pSelect->pSrc->a[0];
-      dest.iSDParm = pItem->regReturn;
-      regFromSelect = pItem->regResult;
-      nColumn = pItem->pSelect->pEList->nExpr;
+      dest.iSDParm = pItem->sq.regReturn;
+      regFromSelect = pItem->sq.regResult;
+      nColumn = pItem->sq.pSelect->pEList->nExpr;
       ExplainQueryPlan((pParse, 0, "SCAN %S", pItem));
       if( bIdListInOrder && nColumn==pTab->nCol ){
         regData = regFromSelect;
@@ -3032,7 +3033,7 @@ static int xferOptimization(
   if( pSelect->pSrc->nSrc!=1 ){
     return 0;   /* FROM clause must have exactly one term */
   }
-  if( pSelect->pSrc->a[0].pSelect ){
+  if( pSelect->pSrc->a[0].sq.pSelect ){
     return 0;   /* FROM clause cannot contain a subquery */
   }
   if( pSelect->pWhere ){
diff --git a/src/parse.y b/src/parse.y
index a605ad6912..9e656d0bc7 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -743,8 +743,8 @@ seltablist(A) ::= stl_prefix(A) nm(Y) dbnm(D) LP exprlist(E) RP as(Z) on_using(N
         assert( pOld->fg.fixedSchema==0 );
         pNew->zName = pOld->zName;
         pNew->u4.zDatabase = pOld->u4.zDatabase;
-        pNew->pSelect = pOld->pSelect;
-        if( pNew->pSelect && (pNew->pSelect->selFlags & SF_NestedFrom)!=0 ){
+        pNew->sq.pSelect = pOld->sq.pSelect;
+        if( pNew->sq.pSelect && (pNew->sq.pSelect->selFlags & SF_NestedFrom)!=0 ){
           pNew->fg.isNestedFrom = 1;
         }
         if( pOld->fg.isTabFunc ){
@@ -754,7 +754,7 @@ seltablist(A) ::= stl_prefix(A) nm(Y) dbnm(D) LP exprlist(E) RP as(Z) on_using(N
           pNew->fg.isTabFunc = 1;
         }
         pOld->zName = pOld->u4.zDatabase = 0;
-        pOld->pSelect = 0;
+        pOld->sq.pSelect = 0;
       }
       sqlite3SrcListDelete(pParse->db, F);
     }else{
diff --git a/src/printf.c b/src/printf.c
index 12dd91a781..027905d26f 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -856,7 +856,7 @@ void sqlite3_str_vappendf(
         }else if( pItem->zAlias ){
           sqlite3_str_appendall(pAccum, pItem->zAlias);
         }else{
-          Select *pSel = pItem->pSelect;
+          Select *pSel = pItem->sq.pSelect;
           assert( pSel!=0 ); /* Because of tag-20240424-1 */
           if( pSel->selFlags & SF_NestedFrom ){
             sqlite3_str_appendf(pAccum, "(join-%u)", pSel->selId);
diff --git a/src/resolve.c b/src/resolve.c
index dbb54198cb..02a48d6993 100644
--- a/src/resolve.c
+++ b/src/resolve.c
@@ -215,7 +215,7 @@ static void extendFJMatch(
   if( pNew ){
     pNew->iTable = pMatch->iCursor;
     pNew->iColumn = iColumn;
-    pNew->y.pTab = pMatch->pTab;
+    pNew->y.pTab = pMatch->pSTab;
     assert( (pMatch->fg.jointype & (JT_LEFT|JT_LTORJ))!=0 );
     ExprSetProperty(pNew, EP_CanBeNull);
     *ppList = sqlite3ExprListAppend(pParse, *ppList, pNew);
@@ -346,10 +346,10 @@ static int lookupName(
     if( pSrcList ){
       for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
         u8 hCol;
-        pTab = pItem->pTab;
+        pTab = pItem->pSTab;
         assert( pTab!=0 && pTab->zName!=0 );
         assert( pTab->nCol>0 || pParse->nErr );
-        assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->pSelect) );
+        assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->sq.pSelect));
         if( pItem->fg.isNestedFrom ){
           /* In this case, pItem is a subquery that has been formed from a
           ** parenthesized subset of the FROM clause terms.  Example:
@@ -358,8 +358,8 @@ static int lookupName(
           **             This pItem -------------^
           */
           int hit = 0;
-          assert( pItem->pSelect!=0 );
-          pEList = pItem->pSelect->pEList;
+          assert( pItem->sq.pSelect!=0 );
+          pEList = pItem->sq.pSelect->pEList;
           assert( pEList!=0 );
           assert( pEList->nExpr==pTab->nCol );
           for(j=0; j<pEList->nExpr; j++){
@@ -483,8 +483,8 @@ static int lookupName(
           if( cntTab==0
            || (cntTab==1
                && ALWAYS(pMatch!=0)
-               && ALWAYS(pMatch->pTab!=0)
-               && (pMatch->pTab->tabFlags & TF_Ephemeral)!=0
+               && ALWAYS(pMatch->pSTab!=0)
+               && (pMatch->pSTab->tabFlags & TF_Ephemeral)!=0
                && (pTab->tabFlags & TF_Ephemeral)==0)
           ){
             cntTab = 1;
@@ -505,7 +505,7 @@ static int lookupName(
       if( pMatch ){
         pExpr->iTable = pMatch->iCursor;
         assert( ExprUseYTab(pExpr) );
-        pExpr->y.pTab = pMatch->pTab;
+        pExpr->y.pTab = pMatch->pSTab;
         if( (pMatch->fg.jointype & (JT_LEFT|JT_LTORJ))!=0 ){
           ExprSetProperty(pExpr, EP_CanBeNull);
         }
@@ -547,7 +547,7 @@ static int lookupName(
       if( (pNC->ncFlags & NC_UUpsert)!=0 && zTab!=0 ){
         Upsert *pUpsert = pNC->uNC.pUpsert;
         if( pUpsert && sqlite3StrICmp("excluded",zTab)==0 ){
-          pTab = pUpsert->pUpsertSrc->a[0].pTab;
+          pTab = pUpsert->pUpsertSrc->a[0].pSTab;
           pExpr->iTable = EXCLUDED_TABLE_NUMBER;
         }
       }
@@ -630,11 +630,11 @@ static int lookupName(
      && pMatch
      && (pNC->ncFlags & (NC_IdxExpr|NC_GenCol))==0
      && sqlite3IsRowid(zCol)
-     && ALWAYS(VisibleRowid(pMatch->pTab) || pMatch->fg.isNestedFrom)
+     && ALWAYS(VisibleRowid(pMatch->pSTab) || pMatch->fg.isNestedFrom)
     ){
       cnt = cntTab;
 #if SQLITE_ALLOW_ROWID_IN_VIEW+0==2
-      if( pMatch->pTab!=0 && IsView(pMatch->pTab) ){
+      if( pMatch->pSTab!=0 && IsView(pMatch->pSTab) ){
         eNewExprOp = TK_NULL;
       }
 #endif
@@ -871,7 +871,7 @@ Expr *sqlite3CreateColumnExpr(sqlite3 *db, SrcList *pSrc, int iSrc, int iCol){
     SrcItem *pItem = &pSrc->a[iSrc];
     Table *pTab;
     assert( ExprUseYTab(p) );
-    pTab = p->y.pTab = pItem->pTab;
+    pTab = p->y.pTab = pItem->pSTab;
     p->iTable = pItem->iCursor;
     if( p->y.pTab->iPKey==iCol ){
       p->iColumn = -1;
@@ -990,7 +990,7 @@ static int resolveExprStep(Walker *pWalker, Expr *pExpr){
       pItem = pSrcList->a;
       pExpr->op = TK_COLUMN;
       assert( ExprUseYTab(pExpr) );
-      pExpr->y.pTab = pItem->pTab;
+      pExpr->y.pTab = pItem->pSTab;
       pExpr->iTable = pItem->iCursor;
       pExpr->iColumn--;
       pExpr->affExpr = SQLITE_AFF_INTEGER;
@@ -1880,7 +1880,7 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
     ** moves the pOrderBy down to the sub-query. It will be moved back
     ** after the names have been resolved.  */
     if( p->selFlags & SF_Converted ){
-      Select *pSub = p->pSrc->a[0].pSelect;
+      Select *pSub = p->pSrc->a[0].sq.pSelect;
       assert( p->pSrc->nSrc==1 && p->pOrderBy );
       assert( pSub->pPrior && pSub->pOrderBy==0 );
       pSub->pOrderBy = p->pOrderBy;
@@ -1892,13 +1892,14 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
     if( pOuterNC ) pOuterNC->nNestedSelect++;
     for(i=0; i<p->pSrc->nSrc; i++){
       SrcItem *pItem = &p->pSrc->a[i];
-      assert( pItem->zName!=0 || pItem->pSelect!=0 );/* Test of tag-20240424-1*/
-      if( pItem->pSelect && (pItem->pSelect->selFlags & SF_Resolved)==0 ){
+      assert( pItem->zName!=0
+              || pItem->sq.pSelect!=0 );  /* Test of tag-20240424-1*/
+      if( pItem->sq.pSelect && (pItem->sq.pSelect->selFlags & SF_Resolved)==0 ){
         int nRef = pOuterNC ? pOuterNC->nRef : 0;
         const char *zSavedContext = pParse->zAuthContext;
 
         if( pItem->zName ) pParse->zAuthContext = pItem->zName;
-        sqlite3ResolveSelectNames(pParse, pItem->pSelect, pOuterNC);
+        sqlite3ResolveSelectNames(pParse, pItem->sq.pSelect, pOuterNC);
         pParse->zAuthContext = zSavedContext;
         if( pParse->nErr ) return WRC_Abort;
         assert( db->mallocFailed==0 );
@@ -2000,7 +2001,7 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
     ** These integers will be replaced by copies of the corresponding result
     ** set expressions by the call to resolveOrderGroupBy() below.  */
     if( p->selFlags & SF_Converted ){
-      Select *pSub = p->pSrc->a[0].pSelect;
+      Select *pSub = p->pSrc->a[0].sq.pSelect;
       p->pOrderBy = pSub->pOrderBy;
       pSub->pOrderBy = 0;
     }
@@ -2267,7 +2268,7 @@ int sqlite3ResolveSelfReference(
   if( pTab ){
     sSrc.nSrc = 1;
     sSrc.a[0].zName = pTab->zName;
-    sSrc.a[0].pTab = pTab;
+    sSrc.a[0].pSTab = pTab;
     sSrc.a[0].iCursor = -1;
     if( pTab->pSchema!=pParse->db->aDb[1].pSchema ){
       /* Cause EP_FromDDL to be set on TK_FUNCTION nodes of non-TEMP
diff --git a/src/select.c b/src/select.c
index 634f06e301..5f55b402cf 100644
--- a/src/select.c
+++ b/src/select.c
@@ -332,11 +332,11 @@ int sqlite3ColumnIndex(Table *pTab, const char *zCol){
 */
 void sqlite3SrcItemColumnUsed(SrcItem *pItem, int iCol){
   assert( pItem!=0 );
-  assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->pSelect) );
+  assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->sq.pSelect) );
   if( pItem->fg.isNestedFrom ){
     ExprList *pResults;
-    assert( pItem->pSelect!=0 );
-    pResults = pItem->pSelect->pEList;
+    assert( pItem->sq.pSelect!=0 );
+    pResults = pItem->sq.pSelect->pEList;
     assert( pResults!=0 );
     assert( iCol>=0 && iCol<pResults->nExpr );
     pResults->a[iCol].fg.bUsed = 1;
@@ -370,9 +370,9 @@ static int tableAndColumnIndex(
   assert( (piTab==0)==(piCol==0) );  /* Both or neither are NULL */
 
   for(i=iStart; i<=iEnd; i++){
-    iCol = sqlite3ColumnIndex(pSrc->a[i].pTab, zCol);
+    iCol = sqlite3ColumnIndex(pSrc->a[i].pSTab, zCol);
     if( iCol>=0
-     && (bIgnoreHidden==0 || IsHiddenColumn(&pSrc->a[i].pTab->aCol[iCol])==0)
+     && (bIgnoreHidden==0 || IsHiddenColumn(&pSrc->a[i].pSTab->aCol[iCol])==0)
     ){
       if( piTab ){
         sqlite3SrcItemColumnUsed(&pSrc->a[i], iCol);
@@ -501,10 +501,10 @@ static int sqlite3ProcessJoin(Parse *pParse, Select *p){
   pLeft = &pSrc->a[0];
   pRight = &pLeft[1];
   for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
-    Table *pRightTab = pRight->pTab;
+    Table *pRightTab = pRight->pSTab;
     u32 joinType;
 
-    if( NEVER(pLeft->pTab==0 || pRightTab==0) ) continue;
+    if( NEVER(pLeft->pSTab==0 || pRightTab==0) ) continue;
     joinType = (pRight->fg.jointype & JT_OUTER)!=0 ? EP_OuterON : EP_InnerON;
 
     /* If this is a NATURAL join, synthesize an appropriate USING clause
@@ -1930,8 +1930,8 @@ static const char *columnTypeImpl(
         SrcList *pTabList = pNC->pSrcList;
         for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
         if( j<pTabList->nSrc ){
-          pTab = pTabList->a[j].pTab;
-          pS = pTabList->a[j].pSelect;
+          pTab = pTabList->a[j].pSTab;
+          pS = pTabList->a[j].sq.pSelect;
         }else{
           pNC = pNC->pNext;
         }
@@ -3983,7 +3983,7 @@ static void substSelect(
     pSrc = p->pSrc;
     assert( pSrc!=0 );
     for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
-      substSelect(pSubst, pItem->pSelect, 1);
+      substSelect(pSubst, pItem->sq.pSelect, 1);
       if( pItem->fg.isTabFunc ){
         substExprList(pSubst, pItem->u1.pFuncArg);
       }
@@ -4014,7 +4014,7 @@ static void recomputeColumnsUsed(
   SrcItem *pSrcItem                /* Which FROM clause item to recompute */
 ){
   Walker w;
-  if( NEVER(pSrcItem->pTab==0) ) return;
+  if( NEVER(pSrcItem->pSTab==0) ) return;
   memset(&w, 0, sizeof(w));
   w.xExprCallback = recomputeColumnsUsedExpr;
   w.xSelectCallback = sqlite3SelectWalkNoop;
@@ -4054,7 +4054,7 @@ static void srclistRenumberCursors(
         aCsrMap[pItem->iCursor+1] = pParse->nTab++;
       }
       pItem->iCursor = aCsrMap[pItem->iCursor+1];
-      for(p=pItem->pSelect; p; p=p->pPrior){
+      for(p=pItem->sq.pSelect; p; p=p->pPrior){
         srclistRenumberCursors(pParse, aCsrMap, p->pSrc, -1);
       }
     }
@@ -4366,7 +4366,7 @@ static int flattenSubquery(
   assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
   pSubitem = &pSrc->a[iFrom];
   iParent = pSubitem->iCursor;
-  pSub = pSubitem->pSelect;
+  pSub = pSubitem->sq.pSelect;
   assert( pSub!=0 );
 
 #ifndef SQLITE_OMIT_WINDOWFUNC
@@ -4419,7 +4419,7 @@ static int flattenSubquery(
   */
   if( (pSubitem->fg.jointype & (JT_OUTER|JT_LTORJ))!=0 ){
     if( pSubSrc->nSrc>1                        /* (3a) */
-     || IsVirtual(pSubSrc->a[0].pTab)          /* (3b) */
+     || IsVirtual(pSubSrc->a[0].pSTab)         /* (3b) */
      || (p->selFlags & SF_Distinct)!=0         /* (3d) */
      || (pSubitem->fg.jointype & JT_RIGHT)!=0  /* (26) */
     ){
@@ -4505,7 +4505,7 @@ static int flattenSubquery(
   pParse->zAuthContext = zSavedAuthContext;
 
   /* Delete the transient structures associated with the subquery */
-  pSub1 = pSubitem->pSelect;
+  pSub1 = pSubitem->sq.pSelect;
   if( pSubitem->fg.fixedSchema==0 ){
     sqlite3DbFree(db, pSubitem->u4.zDatabase);
     pSubitem->u4.zDatabase = 0;
@@ -4514,7 +4514,7 @@ static int flattenSubquery(
   sqlite3DbFree(db, pSubitem->zAlias);
   pSubitem->zName = 0;
   pSubitem->zAlias = 0;
-  pSubitem->pSelect = 0;
+  pSubitem->sq.pSelect = 0;
   assert( pSubitem->fg.isUsing!=0 || pSubitem->u3.pOn==0 );
 
   /* If the sub-query is a compound SELECT statement, then (by restrictions
@@ -4555,8 +4555,8 @@ static int flattenSubquery(
     ExprList *pOrderBy = p->pOrderBy;
     Expr *pLimit = p->pLimit;
     Select *pPrior = p->pPrior;
-    Table *pItemTab = pSubitem->pTab;
-    pSubitem->pTab = 0;
+    Table *pItemTab = pSubitem->pSTab;
+    pSubitem->pSTab = 0;
     p->pOrderBy = 0;
     p->pPrior = 0;
     p->pLimit = 0;
@@ -4564,7 +4564,7 @@ static int flattenSubquery(
     p->pLimit = pLimit;
     p->pOrderBy = pOrderBy;
     p->op = TK_ALL;
-    pSubitem->pTab = pItemTab;
+    pSubitem->pSTab = pItemTab;
     if( pNew==0 ){
       p->pPrior = pPrior;
     }else{
@@ -4579,11 +4579,11 @@ static int flattenSubquery(
       TREETRACE(0x4,pParse,p,("compound-subquery flattener"
                               " creates %u as peer\n",pNew->selId));
     }
-    assert( pSubitem->pSelect==0 );
+    assert( pSubitem->sq.pSelect==0 );
   }
   sqlite3DbFree(db, aCsrMap);
   if( db->mallocFailed ){
-    pSubitem->pSelect = pSub1;
+    pSubitem->sq.pSelect = pSub1;
     return 1;
   }
 
@@ -4594,8 +4594,8 @@ static int flattenSubquery(
   **
   ** pSubitem->pTab is always non-NULL by test restrictions and tests above.
   */
-  if( ALWAYS(pSubitem->pTab!=0) ){
-    Table *pTabToDel = pSubitem->pTab;
+  if( ALWAYS(pSubitem->pSTab!=0) ){
+    Table *pTabToDel = pSubitem->pSTab;
     if( pTabToDel->nTabRef==1 ){
       Parse *pToplevel = sqlite3ParseToplevel(pParse);
       sqlite3ParserAddCleanup(pToplevel, sqlite3DeleteTableGeneric, pTabToDel);
@@ -4603,7 +4603,7 @@ static int flattenSubquery(
     }else{
       pTabToDel->nTabRef--;
     }
-    pSubitem->pTab = 0;
+    pSubitem->pSTab = 0;
   }
 
   /* The following loop runs once for each term in a compound-subquery
@@ -5344,10 +5344,10 @@ static int disableUnusedSubqueryResultColumns(SrcItem *pItem){
   if( pItem->fg.isCorrelated || pItem->fg.isCte ){
     return 0;
   }
-  assert( pItem->pTab!=0 );
-  pTab = pItem->pTab;
-  assert( pItem->pSelect!=0 );
-  pSub = pItem->pSelect;
+  assert( pItem->pSTab!=0 );
+  pTab = pItem->pSTab;
+  assert( pItem->sq.pSelect!=0 );
+  pSub = pItem->sq.pSelect;
   assert( pSub->pEList->nExpr==pTab->nCol );
   for(pX=pSub; pX; pX=pX->pPrior){
     if( (pX->selFlags & (SF_Distinct|SF_Aggregate))!=0 ){
@@ -5476,13 +5476,13 @@ static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){
   if( p->pWhere
    || p->pEList->nExpr!=1
    || p->pSrc->nSrc!=1
-   || p->pSrc->a[0].pSelect
+   || p->pSrc->a[0].sq.pSelect
    || pAggInfo->nFunc!=1
    || p->pHaving
   ){
     return 0;
   }
-  pTab = p->pSrc->a[0].pTab;
+  pTab = p->pSrc->a[0].pSTab;
   assert( pTab!=0 );
   assert( !IsView(pTab) );
   if( !IsOrdinaryTable(pTab) ) return 0;
@@ -5507,7 +5507,7 @@ static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){
 ** pFrom->pIndex and return SQLITE_OK.
 */
 int sqlite3IndexedByLookup(Parse *pParse, SrcItem *pFrom){
-  Table *pTab = pFrom->pTab;
+  Table *pTab = pFrom->pSTab;
   char *zIndexedBy = pFrom->u1.zIndexedBy;
   Index *pIdx;
   assert( pTab!=0 );
@@ -5709,7 +5709,7 @@ static int resolveFromTermToCte(
   Cte *pCte;               /* Matched CTE (or NULL if no match) */
   With *pWith;             /* The matching WITH */
 
-  assert( pFrom->pTab==0 );
+  assert( pFrom->pSTab==0 );
   if( pParse->pWith==0 ){
     /* There are no WITH clauses in the stack.  No match is possible */
     return 0;
@@ -5756,7 +5756,7 @@ static int resolveFromTermToCte(
     }
     if( cannotBeFunction(pParse, pFrom) ) return 2;
 
-    assert( pFrom->pTab==0 );
+    assert( pFrom->pSTab==0 );
     pTab = sqlite3DbMallocZero(db, sizeof(Table));
     if( pTab==0 ) return 2;
     pCteUse = pCte->pUse;
@@ -5770,16 +5770,16 @@ static int resolveFromTermToCte(
       }
       pCteUse->eM10d = pCte->eM10d;
     }
-    pFrom->pTab = pTab;
+    pFrom->pSTab = pTab;
     pTab->nTabRef = 1;
     pTab->zName = sqlite3DbStrDup(db, pCte->zName);
     pTab->iPKey = -1;
     pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
     pTab->tabFlags |= TF_Ephemeral | TF_NoVisibleRowid;
-    pFrom->pSelect = sqlite3SelectDup(db, pCte->pSelect, 0);
+    pFrom->sq.pSelect = sqlite3SelectDup(db, pCte->pSelect, 0);
     if( db->mallocFailed ) return 2;
-    pFrom->pSelect->selFlags |= SF_CopyCte;
-    assert( pFrom->pSelect );
+    assert( pFrom->sq.pSelect );
+    pFrom->sq.pSelect->selFlags |= SF_CopyCte;
     if( pFrom->fg.isIndexedBy ){
       sqlite3ErrorMsg(pParse, "no such index: \"%s\"", pFrom->u1.zIndexedBy);
       return 2;
@@ -5789,7 +5789,7 @@ static int resolveFromTermToCte(
     pCteUse->nUse++;
 
     /* Check if this is a recursive CTE. */
-    pRecTerm = pSel = pFrom->pSelect;
+    pRecTerm = pSel = pFrom->sq.pSelect;
     bMayRecursive = ( pSel->op==TK_ALL || pSel->op==TK_UNION );
     while( bMayRecursive && pRecTerm->op==pSel->op ){
       int i;
@@ -5802,7 +5802,7 @@ static int resolveFromTermToCte(
          && pItem->zName!=0
          && 0==sqlite3StrICmp(pItem->zName, pCte->zName)
         ){
-          pItem->pTab = pTab;
+          pItem->pSTab = pTab;
           pTab->nTabRef++;
           pItem->fg.isRecursive = 1;
           if( pRecTerm->selFlags & SF_Recursive ){
@@ -5904,11 +5904,11 @@ void sqlite3SelectPopWith(Walker *pWalker, Select *p){
 ** SQLITE_NOMEM.
 */
 int sqlite3ExpandSubquery(Parse *pParse, SrcItem *pFrom){
-  Select *pSel = pFrom->pSelect;
+  Select *pSel = pFrom->sq.pSelect;
   Table *pTab;
 
   assert( pSel );
-  pFrom->pTab = pTab = sqlite3DbMallocZero(pParse->db, sizeof(Table));
+  pFrom->pSTab = pTab = sqlite3DbMallocZero(pParse->db, sizeof(Table));
   if( pTab==0 ) return SQLITE_NOMEM;
   pTab->nTabRef = 1;
   if( pFrom->zAlias ){
@@ -6028,33 +6028,33 @@ static int selectExpander(Walker *pWalker, Select *p){
   */
   for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
     Table *pTab;
-    assert( pFrom->fg.isRecursive==0 || pFrom->pTab!=0 );
-    if( pFrom->pTab ) continue;
+    assert( pFrom->fg.isRecursive==0 || pFrom->pSTab!=0 );
+    if( pFrom->pSTab ) continue;
     assert( pFrom->fg.isRecursive==0 );
     if( pFrom->zName==0 ){
 #ifndef SQLITE_OMIT_SUBQUERY
-      Select *pSel = pFrom->pSelect;
+      Select *pSel = pFrom->sq.pSelect;
       /* A sub-query in the FROM clause of a SELECT */
       assert( pSel!=0 );
-      assert( pFrom->pTab==0 );
+      assert( pFrom->pSTab==0 );
       if( sqlite3WalkSelect(pWalker, pSel) ) return WRC_Abort;
       if( sqlite3ExpandSubquery(pParse, pFrom) ) return WRC_Abort;
 #endif
 #ifndef SQLITE_OMIT_CTE
     }else if( (rc = resolveFromTermToCte(pParse, pWalker, pFrom))!=0 ){
       if( rc>1 ) return WRC_Abort;
-      pTab = pFrom->pTab;
+      pTab = pFrom->pSTab;
       assert( pTab!=0 );
 #endif
     }else{
       /* An ordinary table or view name in the FROM clause */
-      assert( pFrom->pTab==0 );
-      pFrom->pTab = pTab = sqlite3LocateTableItem(pParse, 0, pFrom);
+      assert( pFrom->pSTab==0 );
+      pFrom->pSTab = pTab = sqlite3LocateTableItem(pParse, 0, pFrom);
       if( pTab==0 ) return WRC_Abort;
       if( pTab->nTabRef>=0xffff ){
         sqlite3ErrorMsg(pParse, "too many references to \"%s\": max 65535",
            pTab->zName);
-        pFrom->pTab = 0;
+        pFrom->pSTab = 0;
         return WRC_Abort;
       }
       pTab->nTabRef++;
@@ -6066,7 +6066,7 @@ static int selectExpander(Walker *pWalker, Select *p){
         i16 nCol;
         u8 eCodeOrig = pWalker->eCode;
         if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
-        assert( pFrom->pSelect==0 );
+        assert( pFrom->sq.pSelect==0 );
         if( IsView(pTab) ){
           if( (db->flags & SQLITE_EnableView)==0
            && pTab->pSchema!=db->aDb[1].pSchema
@@ -6074,7 +6074,7 @@ static int selectExpander(Walker *pWalker, Select *p){
             sqlite3ErrorMsg(pParse, "access to view \"%s\" prohibited",
               pTab->zName);
           }
-          pFrom->pSelect = sqlite3SelectDup(db, pTab->u.view.pSelect, 0);
+          pFrom->sq.pSelect = sqlite3SelectDup(db, pTab->u.view.pSelect, 0);
         }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
         else if( ALWAYS(IsVirtual(pTab))
@@ -6090,7 +6090,7 @@ static int selectExpander(Walker *pWalker, Select *p){
         nCol = pTab->nCol;
         pTab->nCol = -1;
         pWalker->eCode = 1;  /* Turn on Select.selId renumbering */
-        sqlite3WalkSelect(pWalker, pFrom->pSelect);
+        sqlite3WalkSelect(pWalker, pFrom->sq.pSelect);
         pWalker->eCode = eCodeOrig;
         pTab->nCol = nCol;
       }
@@ -6177,7 +6177,7 @@ static int selectExpander(Walker *pWalker, Select *p){
         }
         for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
           int nAdd;                    /* Number of cols including rowid */
-          Table *pTab = pFrom->pTab;   /* Table for this data source */
+          Table *pTab = pFrom->pSTab;  /* Table for this data source */
           ExprList *pNestedFrom;       /* Result-set of a nested FROM clause */
           char *zTabName;              /* AS name for this data source */
           const char *zSchemaName = 0; /* Schema name for this data source */
@@ -6188,10 +6188,11 @@ static int selectExpander(Walker *pWalker, Select *p){
             zTabName = pTab->zName;
           }
           if( db->mallocFailed ) break;
-          assert( (int)pFrom->fg.isNestedFrom == IsNestedFrom(pFrom->pSelect) );
+          assert( (int)pFrom->fg.isNestedFrom ==
+                                         IsNestedFrom(pFrom->sq.pSelect) );
           if( pFrom->fg.isNestedFrom ){
-            assert( pFrom->pSelect!=0 );
-            pNestedFrom = pFrom->pSelect->pEList;
+            assert( pFrom->sq.pSelect!=0 );
+            pNestedFrom = pFrom->sq.pSelect->pEList;
             assert( pNestedFrom!=0 );
             assert( pNestedFrom->nExpr==pTab->nCol );
             assert( VisibleRowid(pTab)==0 || ViewCanHaveRowid );
@@ -6430,11 +6431,11 @@ static void selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
   assert( (p->selFlags & SF_Resolved) );
   pTabList = p->pSrc;
   for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
-    Table *pTab = pFrom->pTab;
+    Table *pTab = pFrom->pSTab;
     assert( pTab!=0 );
     if( (pTab->tabFlags & TF_Ephemeral)!=0 ){
       /* A sub-query in the FROM clause of a SELECT */
-      Select *pSel = pFrom->pSelect;
+      Select *pSel = pFrom->sq.pSelect;
       if( pSel ){
         sqlite3SubqueryColumnTypes(pParse, pTab, pSel, SQLITE_AFF_NONE);
       }
@@ -7084,25 +7085,25 @@ static SrcItem *isSelfJoinView(
   int iFirst, int iEnd        /* Range of FROM-clause entries to search. */
 ){
   SrcItem *pItem;
-  assert( pThis->pSelect!=0 );
-  if( pThis->pSelect->selFlags & SF_PushDown ) return 0;
+  assert( pThis->sq.pSelect!=0 );
+  if( pThis->sq.pSelect->selFlags & SF_PushDown ) return 0;
   while( iFirst<iEnd ){
     Select *pS1;
     pItem = &pTabList->a[iFirst++];
-    if( pItem->pSelect==0 ) continue;
+    if( pItem->sq.pSelect==0 ) continue;
     if( pItem->fg.viaCoroutine ) continue;
     if( pItem->zName==0 ) continue;
-    assert( pItem->pTab!=0 );
-    assert( pThis->pTab!=0 );
-    if( pItem->pTab->pSchema!=pThis->pTab->pSchema ) continue;
+    assert( pItem->pSTab!=0 );
+    assert( pThis->pSTab!=0 );
+    if( pItem->pSTab->pSchema!=pThis->pSTab->pSchema ) continue;
     if( sqlite3_stricmp(pItem->zName, pThis->zName)!=0 ) continue;
-    pS1 = pItem->pSelect;
-    if( pItem->pTab->pSchema==0 && pThis->pSelect->selId!=pS1->selId ){
+    pS1 = pItem->sq.pSelect;
+    if( pItem->pSTab->pSchema==0 && pThis->sq.pSelect->selId!=pS1->selId ){
       /* The query flattener left two different CTE tables with identical
       ** names in the same FROM clause. */
       continue;
     }
-    if( pItem->pSelect->selFlags & SF_PushDown ){
+    if( pItem->sq.pSelect->selFlags & SF_PushDown ){
       /* The view was modified by some other optimization such as
       ** pushDownWhereTerms() */
       continue;
@@ -7160,7 +7161,7 @@ static int countOfViewOptimization(Parse *pParse, Select *p){
   if( pExpr->x.pList!=0 ) return 0;                 /* Must be count(*) */
   if( p->pSrc->nSrc!=1 ) return 0;                  /* One table in FROM  */
   if( ExprHasProperty(pExpr, EP_WinFunc) ) return 0;/* Not a window function */
-  pSub = p->pSrc->a[0].pSelect;
+  pSub = p->pSrc->a[0].sq.pSelect;
   if( pSub==0 ) return 0;                           /* The FROM is a subquery */
   if( pSub->pPrior==0 ) return 0;                   /* Must be a compound */
   if( pSub->selFlags & SF_CopyCte ) return 0;       /* Not a CTE */
@@ -7178,8 +7179,8 @@ static int countOfViewOptimization(Parse *pParse, Select *p){
   db = pParse->db;
   pCount = pExpr;
   pExpr = 0;
-  pSub = p->pSrc->a[0].pSelect;
-  p->pSrc->a[0].pSelect = 0;
+  pSub = p->pSrc->a[0].sq.pSelect;
+  p->pSrc->a[0].sq.pSelect = 0;
   sqlite3SrcListDelete(db, p->pSrc);
   p->pSrc = sqlite3DbMallocZero(pParse->db, sizeof(*p->pSrc));
   while( pSub ){
@@ -7224,12 +7225,12 @@ static int sameSrcAlias(SrcItem *p0, SrcList *pSrc){
   for(i=0; i<pSrc->nSrc; i++){
     SrcItem *p1 = &pSrc->a[i];
     if( p1==p0 ) continue;
-    if( p0->pTab==p1->pTab && 0==sqlite3_stricmp(p0->zAlias, p1->zAlias) ){
+    if( p0->pSTab==p1->pSTab && 0==sqlite3_stricmp(p0->zAlias, p1->zAlias) ){
       return 1;
     }
-    if( p1->pSelect
-     && (p1->pSelect->selFlags & SF_NestedFrom)!=0
-     && sameSrcAlias(p0, p1->pSelect->pSrc)
+    if( p1->sq.pSelect
+     && (p1->sq.pSelect->selFlags & SF_NestedFrom)!=0
+     && sameSrcAlias(p0, p1->sq.pSelect->pSrc)
     ){
       return 1;
     }
@@ -7294,7 +7295,7 @@ static int fromClauseTermCanBeCoroutine(
     if( i==0 ) break;
     i--;
     pItem--;
-    if( pItem->pSelect!=0 ) return 0;                             /* (1c-i) */
+    if( pItem->sq.pSelect!=0 ) return 0;                          /* (1c-i) */
   }
   return 1;
 }
@@ -7405,7 +7406,7 @@ int sqlite3Select(
     if( sameSrcAlias(p0, p->pSrc) ){
       sqlite3ErrorMsg(pParse,
           "target object/alias may not appear in FROM clause: %s",
-          p0->zAlias ? p0->zAlias : p0->pTab->zName
+          p0->zAlias ? p0->zAlias : p0->pSTab->zName
       );
       goto select_end;
     }
@@ -7444,8 +7445,8 @@ int sqlite3Select(
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
   for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
     SrcItem *pItem = &pTabList->a[i];
-    Select *pSub = pItem->pSelect;
-    Table *pTab = pItem->pTab;
+    Select *pSub = pItem->sq.pSelect;
+    Table *pTab = pItem->pSTab;
 
     /* The expander should have already created transient Table objects
     ** even for FROM clause elements such as subqueries that do not correspond
@@ -7698,11 +7699,11 @@ int sqlite3Select(
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
     /* Generate code for all sub-queries in the FROM clause
     */
-    pSub = pItem->pSelect;
-    if( pSub==0 || pItem->addrFillSub!=0 ) continue;
+    pSub = pItem->sq.pSelect;
+    if( pSub==0 || pItem->sq.addrFillSub!=0 ) continue;
 
     /* The code for a subquery should only be generated once. */
-    assert( pItem->addrFillSub==0 );
+    assert( pItem->sq.addrFillSub==0 );
 
     /* Increment Parse.nHeight by the height of the largest expression
     ** tree referred to by this, the parent select. The child select
@@ -7728,7 +7729,8 @@ int sqlite3Select(
         sqlite3TreeViewSelect(0, p, 0);
       }
 #endif
-      assert( pItem->pSelect && (pItem->pSelect->selFlags & SF_PushDown)!=0 );
+      assert( pItem->sq.pSelect 
+           && (pItem->sq.pSelect->selFlags & SF_PushDown)!=0 );
     }else{
       TREETRACE(0x4000,pParse,p,("WHERE-lcause push-down not possible\n"));
     }
@@ -7760,17 +7762,17 @@ int sqlite3Select(
       */
       int addrTop = sqlite3VdbeCurrentAddr(v)+1;
     
-      pItem->regReturn = ++pParse->nMem;
-      sqlite3VdbeAddOp3(v, OP_InitCoroutine, pItem->regReturn, 0, addrTop);
+      pItem->sq.regReturn = ++pParse->nMem;
+      sqlite3VdbeAddOp3(v, OP_InitCoroutine, pItem->sq.regReturn, 0, addrTop);
       VdbeComment((v, "%!S", pItem));
-      pItem->addrFillSub = addrTop;
-      sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn);
+      pItem->sq.addrFillSub = addrTop;
+      sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->sq.regReturn);
       ExplainQueryPlan((pParse, 1, "CO-ROUTINE %!S", pItem));
       sqlite3Select(pParse, pSub, &dest);
-      pItem->pTab->nRowLogEst = pSub->nSelectRow;
+      pItem->pSTab->nRowLogEst = pSub->nSelectRow;
       pItem->fg.viaCoroutine = 1;
-      pItem->regResult = dest.iSdst;
-      sqlite3VdbeEndCoroutine(v, pItem->regReturn);
+      pItem->sq.regResult = dest.iSdst;
+      sqlite3VdbeEndCoroutine(v, pItem->sq.regReturn);
       sqlite3VdbeJumpHere(v, addrTop-1);
       sqlite3ClearTempRegCache(pParse);
     }else if( pItem->fg.isCte && pItem->u2.pCteUse->addrM9e>0 ){
@@ -7788,11 +7790,12 @@ int sqlite3Select(
     }else if( (pPrior = isSelfJoinView(pTabList, pItem, 0, i))!=0 ){
       /* This view has already been materialized by a prior entry in
       ** this same FROM clause.  Reuse it. */
-      if( pPrior->addrFillSub ){
-        sqlite3VdbeAddOp2(v, OP_Gosub, pPrior->regReturn, pPrior->addrFillSub);
+      if( pPrior->sq.addrFillSub ){
+        sqlite3VdbeAddOp2(v, OP_Gosub, pPrior->sq.regReturn,
+                                       pPrior->sq.addrFillSub);
       }
       sqlite3VdbeAddOp2(v, OP_OpenDup, pItem->iCursor, pPrior->iCursor);
-      pSub->nSelectRow = pPrior->pSelect->nSelectRow;
+      pSub->nSelectRow = pPrior->sq.pSelect->nSelectRow;
     }else{
       /* Materialize the view.  If the view is not correlated, generate a
       ** subroutine to do the materialization so that subsequent uses of
@@ -7803,9 +7806,9 @@ int sqlite3Select(
       int addrExplain;
 #endif
 
-      pItem->regReturn = ++pParse->nMem;
+      pItem->sq.regReturn = ++pParse->nMem;
       topAddr = sqlite3VdbeAddOp0(v, OP_Goto);
-      pItem->addrFillSub = topAddr+1;
+      pItem->sq.addrFillSub = topAddr+1;
       pItem->fg.isMaterialized = 1;
       if( pItem->fg.isCorrelated==0 ){
         /* If the subquery is not correlated and if we are not inside of
@@ -7820,17 +7823,17 @@ int sqlite3Select(
 
       ExplainQueryPlan2(addrExplain, (pParse, 1, "MATERIALIZE %!S", pItem));
       sqlite3Select(pParse, pSub, &dest);
-      pItem->pTab->nRowLogEst = pSub->nSelectRow;
+      pItem->pSTab->nRowLogEst = pSub->nSelectRow;
       if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
-      sqlite3VdbeAddOp2(v, OP_Return, pItem->regReturn, topAddr+1);
+      sqlite3VdbeAddOp2(v, OP_Return, pItem->sq.regReturn, topAddr+1);
       VdbeComment((v, "end %!S", pItem));
       sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1);
       sqlite3VdbeJumpHere(v, topAddr);
       sqlite3ClearTempRegCache(pParse);
       if( pItem->fg.isCte && pItem->fg.isCorrelated==0 ){
         CteUse *pCteUse = pItem->u2.pCteUse;
-        pCteUse->addrM9e = pItem->addrFillSub;
-        pCteUse->regRtn = pItem->regReturn;
+        pCteUse->addrM9e = pItem->sq.addrFillSub;
+        pCteUse->regRtn = pItem->sq.regReturn;
         pCteUse->iCur = pItem->iCursor;
         pCteUse->nRowEst = pSub->nSelectRow;
       }
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 75e1f61201..54e4f2db73 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3295,15 +3295,23 @@ struct IdList {
 **
 **    u2.pIBIndex        fg.isIndexedBy && !fg.isCte
 **    u2.pCteUse         fg.isCte       && !fg.isIndexedBy
+**
+**    u3.pOn             fg.isUsing==0
+**    u3.pUsing          fg.isUsing==1
+**
+**    u4.zDatabase       fg.fixedSchema==0
+**    u4.pSchema         fg.fixedSchema==1
 */
 struct SrcItem {
   char *zName;      /* Name of the table */
   char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
-  Table *pTab;      /* An SQL table corresponding to zName */
-  Select *pSelect;  /* A SELECT statement used in place of a table name */
-  int addrFillSub;  /* Address of subroutine to initialize a subquery */
-  int regReturn;    /* Register holding return address of addrFillSub */
-  int regResult;    /* Registers holding results of a co-routine */
+  Table *pSTab;     /* Table object for zName. Mnemonic: Srcitem-TABle */
+  struct SrcItemSubquery {
+    Select *pSelect;  /* A SELECT statement used in place of a table name */
+    int addrFillSub;  /* Address of subroutine to initialize a subquery */
+    int regReturn;    /* Register holding return address of addrFillSub */
+    int regResult;    /* Registers holding results of a co-routine */
+  } sq;
   struct {
     u8 jointype;      /* Type of join between this table and the previous */
     unsigned notIndexed :1;    /* True if there is a NOT INDEXED clause */
diff --git a/src/treeview.c b/src/treeview.c
index 3960d2859e..0c9fdc5266 100644
--- a/src/treeview.c
+++ b/src/treeview.c
@@ -193,9 +193,9 @@ void sqlite3TreeViewSrcList(TreeView *pView, const SrcList *pSrc){
     sqlite3StrAccumInit(&x, 0, zLine, sizeof(zLine), 0);
     x.printfFlags |= SQLITE_PRINTF_INTERNAL;
     sqlite3_str_appendf(&x, "{%d:*} %!S", pItem->iCursor, pItem);
-    if( pItem->pTab ){
+    if( pItem->pSTab ){
       sqlite3_str_appendf(&x, " tab=%Q nCol=%d ptr=%p used=%llx%s",
-           pItem->pTab->zName, pItem->pTab->nCol, pItem->pTab, 
+           pItem->pSTab->zName, pItem->pSTab->nCol, pItem->pSTab, 
            pItem->colUsed,
            pItem->fg.rowidUsed ? "+rowid" : "");
     }
@@ -230,19 +230,19 @@ void sqlite3TreeViewSrcList(TreeView *pView, const SrcList *pSrc){
     sqlite3StrAccumFinish(&x);
     sqlite3TreeViewItem(pView, zLine, i<pSrc->nSrc-1);
     n = 0;
-    if( pItem->pSelect ) n++;
+    if( pItem->sq.pSelect ) n++;
     if( pItem->fg.isTabFunc ) n++;
     if( pItem->fg.isUsing ) n++;
     if( pItem->fg.isUsing ){
       sqlite3TreeViewIdList(pView, pItem->u3.pUsing, (--n)>0, "USING");
     }
-    if( pItem->pSelect ){
-      if( pItem->pTab ){
-        Table *pTab = pItem->pTab;
+    if( pItem->sq.pSelect ){
+      if( pItem->pSTab ){
+        Table *pTab = pItem->pSTab;
         sqlite3TreeViewColumnList(pView, pTab->aCol, pTab->nCol, 1);
       }
-      assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->pSelect) );
-      sqlite3TreeViewSelect(pView, pItem->pSelect, (--n)>0);
+      assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->sq.pSelect) );
+      sqlite3TreeViewSelect(pView, pItem->sq.pSelect, (--n)>0);
     }
     if( pItem->fg.isTabFunc ){
       sqlite3TreeViewExprList(pView, pItem->u1.pFuncArg, 0, "func-args:");
diff --git a/src/trigger.c b/src/trigger.c
index a5a57abf16..170f094eab 100644
--- a/src/trigger.c
+++ b/src/trigger.c
@@ -984,7 +984,7 @@ static int sqlite3ReturningSubqueryCorrelated(Walker *pWalker, Select *pSelect){
   pSrc = pSelect->pSrc;
   assert( pSrc!=0 );
   for(i=0; i<pSrc->nSrc; i++){
-    if( pSrc->a[i].pTab==pWalker->u.pTab ){
+    if( pSrc->a[i].pSTab==pWalker->u.pTab ){
       testcase( pSelect->selFlags & SF_Correlated );
       pSelect->selFlags |= SF_Correlated;
       pWalker->eCode = 1;
@@ -1055,7 +1055,7 @@ static void codeReturningTrigger(
   sSelect.pEList = sqlite3ExprListDup(db, pReturning->pReturnEL, 0);
   sSelect.pSrc = &sFrom;
   sFrom.nSrc = 1;
-  sFrom.a[0].pTab = pTab;
+  sFrom.a[0].pSTab = pTab;
   sFrom.a[0].zName = pTab->zName; /* tag-20240424-1 */
   sFrom.a[0].iCursor = -1;
   sqlite3SelectPrep(pParse, &sSelect, 0);
diff --git a/src/update.c b/src/update.c
index b6068caa79..a8e7f77803 100644
--- a/src/update.c
+++ b/src/update.c
@@ -202,7 +202,7 @@ static void updateFromSelect(
   Expr *pLimit2 = 0;
   ExprList *pOrderBy2 = 0;
   sqlite3 *db = pParse->db;
-  Table *pTab = pTabList->a[0].pTab;
+  Table *pTab = pTabList->a[0].pSTab;
   SrcList *pSrc;
   Expr *pWhere2;
   int eDest;
@@ -226,8 +226,8 @@ static void updateFromSelect(
   if( pSrc ){
     assert( pSrc->a[0].fg.notCte );
     pSrc->a[0].iCursor = -1;
-    pSrc->a[0].pTab->nTabRef--;
-    pSrc->a[0].pTab = 0;
+    pSrc->a[0].pSTab->nTabRef--;
+    pSrc->a[0].pSTab = 0;
   }
   if( pPk ){
     for(i=0; i<pPk->nKeyCol; i++){
diff --git a/src/upsert.c b/src/upsert.c
index f74d4fabf5..82295d52ae 100644
--- a/src/upsert.c
+++ b/src/upsert.c
@@ -104,7 +104,7 @@ int sqlite3UpsertAnalyzeTarget(
   int nClause = 0;        /* Counter of ON CONFLICT clauses */
 
   assert( pTabList->nSrc==1 );
-  assert( pTabList->a[0].pTab!=0 );
+  assert( pTabList->a[0].pSTab!=0 );
   assert( pUpsert!=0 );
   assert( pUpsert->pUpsertTarget!=0 );
 
@@ -123,7 +123,7 @@ int sqlite3UpsertAnalyzeTarget(
     if( rc ) return rc;
   
     /* Check to see if the conflict target matches the rowid. */  
-    pTab = pTabList->a[0].pTab;
+    pTab = pTabList->a[0].pSTab;
     pTarget = pUpsert->pUpsertTarget;
     iCursor = pTabList->a[0].iCursor;
     if( HasRowid(pTab) 
diff --git a/src/walker.c b/src/walker.c
index 0fe4a1d379..27963c2234 100644
--- a/src/walker.c
+++ b/src/walker.c
@@ -171,7 +171,7 @@ int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
   pSrc = p->pSrc;
   if( ALWAYS(pSrc) ){
     for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
-      if( pItem->pSelect && sqlite3WalkSelect(pWalker, pItem->pSelect) ){
+      if( pItem->sq.pSelect && sqlite3WalkSelect(pWalker, pItem->sq.pSelect) ){
         return WRC_Abort;
       }
       if( pItem->fg.isTabFunc
diff --git a/src/where.c b/src/where.c
index 631b7581fb..ded5f06816 100644
--- a/src/where.c
+++ b/src/where.c
@@ -644,7 +644,7 @@ static int isDistinctRedundant(
   ** clause is redundant. */
   if( pTabList->nSrc!=1 ) return 0;
   iBase = pTabList->a[0].iCursor;
-  pTab = pTabList->a[0].pTab;
+  pTab = pTabList->a[0].pSTab;
 
   /* If any of the expressions is an IPK column on table iBase, then return
   ** true. Note: The (p->iTable==iBase) part of this test may be false if the
@@ -908,10 +908,10 @@ static int termCanDriveIndex(
   assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
   leftCol = pTerm->u.x.leftColumn;
   if( leftCol<0 ) return 0;
-  aff = pSrc->pTab->aCol[leftCol].affinity;
+  aff = pSrc->pSTab->aCol[leftCol].affinity;
   if( !sqlite3IndexAffinityOk(pTerm->pExpr, aff) ) return 0;
   testcase( pTerm->pExpr->op==TK_IS );
-  return columnIsGoodIndexCandidate(pSrc->pTab, leftCol);
+  return columnIsGoodIndexCandidate(pSrc->pSTab, leftCol);
 }
 #endif
 
@@ -1019,7 +1019,7 @@ static SQLITE_NOINLINE void constructAutomaticIndex(
   nKeyCol = 0;
   pTabList = pWC->pWInfo->pTabList;
   pSrc = &pTabList->a[pLevel->iFrom];
-  pTable = pSrc->pTab;
+  pTable = pSrc->pSTab;
   pWCEnd = &pWC->a[pWC->nTerm];
   pLoop = pLevel->pWLoop;
   idxCols = 0;
@@ -1161,12 +1161,12 @@ static SQLITE_NOINLINE void constructAutomaticIndex(
   /* Fill the automatic index with content */
   assert( pSrc == &pWC->pWInfo->pTabList->a[pLevel->iFrom] );
   if( pSrc->fg.viaCoroutine ){
-    int regYield = pSrc->regReturn;
+    int regYield = pSrc->sq.regReturn;
     addrCounter = sqlite3VdbeAddOp2(v, OP_Integer, 0, 0);
-    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pSrc->addrFillSub);
+    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pSrc->sq.addrFillSub);
     addrTop =  sqlite3VdbeAddOp1(v, OP_Yield, regYield);
     VdbeCoverage(v);
-    VdbeComment((v, "next row of %s", pSrc->pTab->zName));
+    VdbeComment((v, "next row of %s", pSrc->pSTab->zName));
   }else{
     addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, pLevel->iTabCur); VdbeCoverage(v);
   }
@@ -1192,7 +1192,7 @@ static SQLITE_NOINLINE void constructAutomaticIndex(
     testcase( pParse->db->mallocFailed );
     assert( pLevel->iIdxCur>0 );
     translateColumnToCopy(pParse, addrTop, pLevel->iTabCur,
-                          pSrc->regResult, pLevel->iIdxCur);
+                          pSrc->sq.regResult, pLevel->iIdxCur);
     sqlite3VdbeGoto(v, addrTop);
     pSrc->fg.viaCoroutine = 0;
   }else{
@@ -1283,7 +1283,7 @@ static SQLITE_NOINLINE void sqlite3ConstructBloomFilter(
     iSrc = pLevel->iFrom;
     pItem = &pTabList->a[iSrc];
     assert( pItem!=0 );
-    pTab = pItem->pTab;
+    pTab = pItem->pSTab;
     assert( pTab!=0 );
     sz = sqlite3LogEstToInt(pTab->nRowLogEst);
     if( sz<10000 ){
@@ -1314,7 +1314,7 @@ static SQLITE_NOINLINE void sqlite3ConstructBloomFilter(
       int r1 = sqlite3GetTempRange(pParse, n);
       int jj;
       for(jj=0; jj<n; jj++){
-        assert( pIdx->pTable==pItem->pTab );
+        assert( pIdx->pTable==pItem->pSTab );
         sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iCur, jj, r1+jj);
       }
       sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, n);
@@ -1395,7 +1395,7 @@ static sqlite3_index_info *allocateIndexInfo(
   WhereClause *p;
 
   assert( pSrc!=0 );
-  pTab = pSrc->pTab;
+  pTab = pSrc->pSTab;
   assert( pTab!=0 );
   assert( IsVirtual(pTab) );
 
@@ -2403,7 +2403,7 @@ void sqlite3WhereLoopPrint(const WhereLoop *p, const WhereClause *pWC){
     WhereInfo *pWInfo = pWC->pWInfo;
     int nb = 1+(pWInfo->pTabList->nSrc+3)/4;
     SrcItem *pItem = pWInfo->pTabList->a + p->iTab;
-    Table *pTab = pItem->pTab;
+    Table *pTab = pItem->pSTab;
     Bitmask mAll = (((Bitmask)1)<<(nb*4)) - 1;
     sqlite3DebugPrintf("%c%2d.%0*llx.%0*llx", p->cId,
                        p->iTab, nb, p->maskSelf, nb, p->prereq & mAll);
@@ -3391,7 +3391,7 @@ static int whereLoopAddBtreeIndex(
     **   2.  Stepping forward in the index pNew->nOut times to find all
     **       additional matching entries.
     */
-    assert( pSrc->pTab->szTabRow>0 );
+    assert( pSrc->pSTab->szTabRow>0 );
     if( pProbe->idxType==SQLITE_IDXTYPE_IPK ){
       /* The pProbe->szIdxRow is low for an IPK table since the interior
       ** pages are small.  Thus szIdxRow gives a good estimate of seek cost.
@@ -3399,7 +3399,7 @@ static int whereLoopAddBtreeIndex(
       ** under-estimate the scanning cost. */
       rCostIdx = pNew->nOut + 16;
     }else{
-      rCostIdx = pNew->nOut + 1 + (15*pProbe->szIdxRow)/pSrc->pTab->szTabRow;
+      rCostIdx = pNew->nOut + 1 + (15*pProbe->szIdxRow)/pSrc->pSTab->szTabRow;
     }
     rCostIdx = sqlite3LogEstAdd(rLogSize, rCostIdx);
 
@@ -3864,9 +3864,9 @@ static int whereLoopAddBtree(
   pWInfo = pBuilder->pWInfo;
   pTabList = pWInfo->pTabList;
   pSrc = pTabList->a + pNew->iTab;
-  pTab = pSrc->pTab;
+  pTab = pSrc->pSTab;
   pWC = pBuilder->pWC;
-  assert( !IsVirtual(pSrc->pTab) );
+  assert( !IsVirtual(pSrc->pSTab) );
 
   if( pSrc->fg.isIndexedBy ){
     assert( pSrc->fg.isCte==0 );
@@ -3891,7 +3891,7 @@ static int whereLoopAddBtree(
     sPk.idxType = SQLITE_IDXTYPE_IPK;
     aiRowEstPk[0] = pTab->nRowLogEst;
     aiRowEstPk[1] = 0;
-    pFirst = pSrc->pTab->pIndex;
+    pFirst = pSrc->pSTab->pIndex;
     if( pSrc->fg.notIndexed==0 ){
       /* The real indices of the table are only considered if the
       ** NOT INDEXED qualifier is omitted from the FROM clause */
@@ -4010,9 +4010,9 @@ static int whereLoopAddBtree(
 #endif
       ApplyCostMultiplier(pNew->rRun, pTab->costMult);
       whereLoopOutputAdjust(pWC, pNew, rSize);
-      if( pSrc->pSelect ){
+      if( pSrc->sq.pSelect ){
         if( pSrc->fg.viaCoroutine ) pNew->wsFlags |= WHERE_COROUTINE;
-        pNew->u.btree.pOrderBy = pSrc->pSelect->pOrderBy;
+        pNew->u.btree.pOrderBy = pSrc->sq.pSelect->pOrderBy;
       }
       rc = whereLoopInsert(pBuilder, pNew);
       pNew->nOut = rSize;
@@ -4238,7 +4238,7 @@ static int whereLoopAddVirtualOne(
   pHidden->mHandleIn = 0;
 
   /* Invoke the virtual table xBestIndex() method */
-  rc = vtabBestIndex(pParse, pSrc->pTab, pIdxInfo);
+  rc = vtabBestIndex(pParse, pSrc->pSTab, pIdxInfo);
   if( rc ){
     if( rc==SQLITE_CONSTRAINT ){
       /* If the xBestIndex method returns SQLITE_CONSTRAINT, that means
@@ -4268,7 +4268,7 @@ static int whereLoopAddVirtualOne(
        || pNew->aLTerm[iTerm]!=0
        || pIdxCons->usable==0
       ){
-        sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pTab->zName);
+        sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pSTab->zName);
         freeIdxStr(pIdxInfo);
         return SQLITE_ERROR;
       }
@@ -4331,7 +4331,7 @@ static int whereLoopAddVirtualOne(
     if( pNew->aLTerm[i]==0 ){
       /* The non-zero argvIdx values must be contiguous.  Raise an
       ** error if they are not */
-      sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pTab->zName);
+      sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pSTab->zName);
       freeIdxStr(pIdxInfo);
       return SQLITE_ERROR;
     }
@@ -4533,7 +4533,7 @@ static int whereLoopAddVirtual(
   pWC = pBuilder->pWC;
   pNew = pBuilder->pNew;
   pSrc = &pWInfo->pTabList->a[pNew->iTab];
-  assert( IsVirtual(pSrc->pTab) );
+  assert( IsVirtual(pSrc->pSTab) );
   p = allocateIndexInfo(pWInfo, pWC, mUnusable, pSrc, &mNoOmit);
   if( p==0 ) return SQLITE_NOMEM_BKPT;
   pNew->rSetup = 0;
@@ -4547,7 +4547,7 @@ static int whereLoopAddVirtual(
   }
 
   /* First call xBestIndex() with all constraints usable. */
-  WHERETRACE(0x800, ("BEGIN %s.addVirtual()\n", pSrc->pTab->zName));
+  WHERETRACE(0x800, ("BEGIN %s.addVirtual()\n", pSrc->pSTab->zName));
   WHERETRACE(0x800, ("  VirtualOne: all usable\n"));
   rc = whereLoopAddVirtualOne(
       pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn, &bRetry
@@ -4629,7 +4629,7 @@ static int whereLoopAddVirtual(
   }
 
   freeIndexInfo(pParse->db, p);
-  WHERETRACE(0x800, ("END %s.addVirtual(), rc=%d\n", pSrc->pTab->zName, rc));
+  WHERETRACE(0x800, ("END %s.addVirtual(), rc=%d\n", pSrc->pSTab->zName, rc));
   return rc;
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -4701,7 +4701,7 @@ static int whereLoopAddOr(
         }
 #endif
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-        if( IsVirtual(pItem->pTab) ){
+        if( IsVirtual(pItem->pSTab) ){
           rc = whereLoopAddVirtual(&sSubBuild, mPrereq, mUnusable);
         }else
 #endif
@@ -4815,7 +4815,7 @@ static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
       mPrereq = 0;
     }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-    if( IsVirtual(pItem->pTab) ){
+    if( IsVirtual(pItem->pSTab) ){
       SrcItem *p;
       for(p=&pItem[1]; p<pEnd; p++){
         if( mUnusable || (p->fg.jointype & (JT_OUTER|JT_CROSS)) ){
@@ -5451,7 +5451,7 @@ static int computeMxChoice(WhereInfo *pWInfo, LogEst nRowEst){
       if( sqlite3WhereTrace&0x4 ){
          SrcItem *pItem = pWInfo->pTabList->a + iLoop;
          sqlite3DebugPrintf("Fact-table %s: %d dimensions, cost reduced %d\n",
-             pItem->zAlias ? pItem->zAlias : pItem->pTab->zName,
+             pItem->zAlias ? pItem->zAlias : pItem->pSTab->zName,
              nDep, rDelta);
       }
 #endif
@@ -6001,7 +6001,7 @@ static int whereShortCut(WhereLoopBuilder *pBuilder){
   if( pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE ) return 0;
   assert( pWInfo->pTabList->nSrc>=1 );
   pItem = pWInfo->pTabList->a;
-  pTab = pItem->pTab;
+  pTab = pItem->pSTab;
   if( IsVirtual(pTab) ) return 0;
   if( pItem->fg.isIndexedBy || pItem->fg.notIndexed ){
     testcase( pItem->fg.isIndexedBy );
@@ -6264,7 +6264,7 @@ static SQLITE_NOINLINE void whereCheckIfBloomFilterIsUseful(
     WhereLoop *pLoop = pWInfo->a[i].pWLoop;
     const unsigned int reqFlags = (WHERE_SELFCULL|WHERE_COLUMN_EQ);
     SrcItem *pItem = &pWInfo->pTabList->a[pLoop->iTab];
-    Table *pTab = pItem->pTab;
+    Table *pTab = pItem->pSTab;
     if( (pTab->tabFlags & TF_HasStat1)==0 ) break;
     pTab->tabFlags |= TF_MaybeReanalyze;
     if( i>=1
@@ -6421,8 +6421,8 @@ static SQLITE_NOINLINE void whereReverseScanOrder(WhereInfo *pWInfo){
     SrcItem *pItem = &pWInfo->pTabList->a[ii];
     if( !pItem->fg.isCte
      || pItem->u2.pCteUse->eM10d!=M10d_Yes
-     || NEVER(pItem->pSelect==0)
-     || pItem->pSelect->pOrderBy==0
+     || NEVER(pItem->sq.pSelect==0)
+     || pItem->sq.pSelect->pOrderBy==0
     ){
       pWInfo->revMask |= MASKBIT(ii);
     }
@@ -6912,15 +6912,15 @@ WhereInfo *sqlite3WhereBegin(
   if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 ){
     int wsFlags = pWInfo->a[0].pWLoop->wsFlags;
     int bOnerow = (wsFlags & WHERE_ONEROW)!=0;
-    assert( !(wsFlags & WHERE_VIRTUALTABLE) || IsVirtual(pTabList->a[0].pTab) );
+    assert( !(wsFlags&WHERE_VIRTUALTABLE) || IsVirtual(pTabList->a[0].pSTab) );
     if( bOnerow || (
         0!=(wctrlFlags & WHERE_ONEPASS_MULTIROW)
-     && !IsVirtual(pTabList->a[0].pTab)
+     && !IsVirtual(pTabList->a[0].pSTab)
      && (0==(wsFlags & WHERE_MULTI_OR) || (wctrlFlags & WHERE_DUPLICATES_OK))
      && OptimizationEnabled(db, SQLITE_OnePass)
     )){
       pWInfo->eOnePass = bOnerow ? ONEPASS_SINGLE : ONEPASS_MULTI;
-      if( HasRowid(pTabList->a[0].pTab) && (wsFlags & WHERE_IDX_ONLY) ){
+      if( HasRowid(pTabList->a[0].pSTab) && (wsFlags & WHERE_IDX_ONLY) ){
         if( wctrlFlags & WHERE_ONEPASS_MULTIROW ){
           bFordelete = OPFLAG_FORDELETE;
         }
@@ -6938,7 +6938,7 @@ WhereInfo *sqlite3WhereBegin(
     SrcItem *pTabItem;
 
     pTabItem = &pTabList->a[pLevel->iFrom];
-    pTab = pTabItem->pTab;
+    pTab = pTabItem->pSTab;
     iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
     pLoop = pLevel->pWLoop;
     if( (pTab->tabFlags & TF_Ephemeral)!=0 || IsView(pTab) ){
@@ -7009,7 +7009,7 @@ WhereInfo *sqlite3WhereBegin(
         iIndexCur = pLevel->iTabCur;
         op = 0;
       }else if( pWInfo->eOnePass!=ONEPASS_OFF ){
-        Index *pJ = pTabItem->pTab->pIndex;
+        Index *pJ = pTabItem->pSTab->pIndex;
         iIndexCur = iAuxArg;
         assert( wctrlFlags & WHERE_ONEPASS_DESIRED );
         while( ALWAYS(pJ) && pJ!=pIx ){
@@ -7076,7 +7076,7 @@ WhereInfo *sqlite3WhereBegin(
       sqlite3VdbeAddOp2(v, OP_Blob, 65536, pRJ->regBloom);
       pRJ->regReturn = ++pParse->nMem;
       sqlite3VdbeAddOp2(v, OP_Null, 0, pRJ->regReturn);
-      assert( pTab==pTabItem->pTab );
+      assert( pTab==pTabItem->pSTab );
       if( HasRowid(pTab) ){
         KeyInfo *pInfo;
         sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRJ->iMatch, 1);
@@ -7116,10 +7116,10 @@ WhereInfo *sqlite3WhereBegin(
     pSrc = &pTabList->a[pLevel->iFrom];
     if( pSrc->fg.isMaterialized ){
       if( pSrc->fg.isCorrelated ){
-        sqlite3VdbeAddOp2(v, OP_Gosub, pSrc->regReturn, pSrc->addrFillSub);
+        sqlite3VdbeAddOp2(v, OP_Gosub, pSrc->sq.regReturn,pSrc->sq.addrFillSub);
       }else{
         int iOnce = sqlite3VdbeAddOp0(v, OP_Once);  VdbeCoverage(v);
-        sqlite3VdbeAddOp2(v, OP_Gosub, pSrc->regReturn, pSrc->addrFillSub);
+        sqlite3VdbeAddOp2(v, OP_Gosub, pSrc->sq.regReturn,pSrc->sq.addrFillSub);
         sqlite3VdbeJumpHere(v, iOnce);
       }
     }
@@ -7334,9 +7334,9 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
         assert( pLevel->iTabCur==pSrc->iCursor );
         if( pSrc->fg.viaCoroutine ){
           int m, n;
-          n = pSrc->regResult;
-          assert( pSrc->pTab!=0 );
-          m = pSrc->pTab->nCol;
+          n = pSrc->sq.regResult;
+          assert( pSrc->pSTab!=0 );
+          m = pSrc->pSTab->nCol;
           sqlite3VdbeAddOp3(v, OP_Null, 0, n, n+m-1);
         }
         sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iTabCur);
@@ -7360,7 +7360,7 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
       sqlite3VdbeJumpHere(v, addr);
     }
     VdbeModuleComment((v, "End WHERE-loop%d: %s", i,
-                     pWInfo->pTabList->a[pLevel->iFrom].pTab->zName));
+                     pWInfo->pTabList->a[pLevel->iFrom].pSTab->zName));
   }
 
   assert( pWInfo->nLevel<=pTabList->nSrc );
@@ -7369,7 +7369,7 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
     VdbeOp *pOp, *pLastOp;
     Index *pIdx = 0;
     SrcItem *pTabItem = &pTabList->a[pLevel->iFrom];
-    Table *pTab = pTabItem->pTab;
+    Table *pTab = pTabItem->pSTab;
     assert( pTab!=0 );
     pLoop = pLevel->pWLoop;
 
@@ -7388,9 +7388,9 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
     */
     if( pTabItem->fg.viaCoroutine ){
       testcase( pParse->db->mallocFailed );
-      assert( pTabItem->regResult>=0 );
+      assert( pTabItem->sq.regResult>=0 );
       translateColumnToCopy(pParse, pLevel->addrBody, pLevel->iTabCur,
-                            pTabItem->regResult, 0);
+                            pTabItem->sq.regResult, 0);
       continue;
     }
 
diff --git a/src/wherecode.c b/src/wherecode.c
index 098af7375e..ebc71d1102 100644
--- a/src/wherecode.c
+++ b/src/wherecode.c
@@ -157,7 +157,7 @@ int sqlite3WhereExplainOneScan(
       assert( pLoop->u.btree.pIndex!=0 );
       pIdx = pLoop->u.btree.pIndex;
       assert( !(flags&WHERE_AUTO_INDEX) || (flags&WHERE_IDX_ONLY) );
-      if( !HasRowid(pItem->pTab) && IsPrimaryKeyIndex(pIdx) ){
+      if( !HasRowid(pItem->pSTab) && IsPrimaryKeyIndex(pIdx) ){
         if( isSearch ){
           zFmt = "PRIMARY KEY";
         }
@@ -254,7 +254,7 @@ int sqlite3WhereExplainBloomFilter(
   sqlite3_str_appendf(&str, "BLOOM FILTER ON %S (", pItem);
   pLoop = pLevel->pWLoop;
   if( pLoop->wsFlags & WHERE_IPK ){
-    const Table *pTab = pItem->pTab;
+    const Table *pTab = pItem->pSTab;
     if( pTab->iPKey>=0 ){
       sqlite3_str_appendf(&str, "%s=?", pTab->aCol[pTab->iPKey].zCnName);
     }else{
@@ -317,7 +317,7 @@ void sqlite3WhereAddScanStatus(
         sqlite3VdbeScanStatusRange(v, addrExplain, -1, pLvl->iIdxCur);
       }
     }else{
-      int addr = pSrclist->a[pLvl->iFrom].addrFillSub;
+      int addr = pSrclist->a[pLvl->iFrom].sq.addrFillSub;
       VdbeOp *pOp = sqlite3VdbeGetOp(v, addr-1);
       assert( sqlite3VdbeDb(v)->mallocFailed || pOp->opcode==OP_InitCoroutine );
       assert( sqlite3VdbeDb(v)->mallocFailed || pOp->p2>addr );
@@ -1454,7 +1454,8 @@ Bitmask sqlite3WhereCodeOneLoopStart(
   iCur = pTabItem->iCursor;
   pLevel->notReady = notReady & ~sqlite3WhereGetMask(&pWInfo->sMaskSet, iCur);
   bRev = (pWInfo->revMask>>iLevel)&1;
-  VdbeModuleComment((v, "Begin WHERE-loop%d: %s",iLevel,pTabItem->pTab->zName));
+  VdbeModuleComment((v, "Begin WHERE-loop%d: %s",
+                     iLevel, pTabItem->pSTab->zName));
 #if WHERETRACE_ENABLED /* 0x4001 */
   if( sqlite3WhereTrace & 0x1 ){
     sqlite3DebugPrintf("Coding level %d of %d:  notReady=%llx  iFrom=%d\n",
@@ -1509,11 +1510,11 @@ Bitmask sqlite3WhereCodeOneLoopStart(
 
   /* Special case of a FROM clause subquery implemented as a co-routine */
   if( pTabItem->fg.viaCoroutine ){
-    int regYield = pTabItem->regReturn;
-    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pTabItem->addrFillSub);
+    int regYield = pTabItem->sq.regReturn;
+    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield,0,pTabItem->sq.addrFillSub);
     pLevel->p2 =  sqlite3VdbeAddOp2(v, OP_Yield, regYield, addrBrk);
     VdbeCoverage(v);
-    VdbeComment((v, "next row of %s", pTabItem->pTab->zName));
+    VdbeComment((v, "next row of %s", pTabItem->pSTab->zName));
     pLevel->op = OP_Goto;
   }else
 
@@ -2242,7 +2243,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
     int untestedTerms = 0;             /* Some terms not completely tested */
     int ii;                            /* Loop counter */
     Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
-    Table *pTab = pTabItem->pTab;
+    Table *pTab = pTabItem->pSTab;
 
     pTerm = pLoop->aLTerm[0];
     assert( pTerm!=0 );
@@ -2701,7 +2702,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
     ** least once.  This is accomplished by storing the PK for the row in
     ** both the iMatch index and the regBloom Bloom filter.
     */
-    pTab = pWInfo->pTabList->a[pLevel->iFrom].pTab;
+    pTab = pWInfo->pTabList->a[pLevel->iFrom].pSTab;
     if( HasRowid(pTab) ){
       r = sqlite3GetTempRange(pParse, 2);
       sqlite3ExprCodeGetColumnOfTable(v, pTab, pLevel->iTabCur, -1, r+1);
@@ -2808,7 +2809,7 @@ SQLITE_NOINLINE void sqlite3WhereRightJoinLoop(
   Bitmask mAll = 0;
   int k;
 
-  ExplainQueryPlan((pParse, 1, "RIGHT-JOIN %s", pTabItem->pTab->zName));
+  ExplainQueryPlan((pParse, 1, "RIGHT-JOIN %s", pTabItem->pSTab->zName));
   sqlite3VdbeNoJumpsOutsideSubrtn(v, pRJ->addrSubrtn, pRJ->endSubrtn,
                                   pRJ->regReturn);
   for(k=0; k<iLevel; k++){
@@ -2819,8 +2820,8 @@ SQLITE_NOINLINE void sqlite3WhereRightJoinLoop(
     mAll |= pWInfo->a[k].pWLoop->maskSelf;
     if( pRight->fg.viaCoroutine ){
       sqlite3VdbeAddOp3(
-          v, OP_Null, 0, pRight->regResult, 
-          pRight->regResult + pRight->pSelect->pEList->nExpr-1
+          v, OP_Null, 0, pRight->sq.regResult, 
+          pRight->sq.regResult + pRight->sq.pSelect->pEList->nExpr-1
       );
     }
     sqlite3VdbeAddOp1(v, OP_NullRow, pWInfo->a[k].iTabCur);
@@ -2858,7 +2859,7 @@ SQLITE_NOINLINE void sqlite3WhereRightJoinLoop(
     int nPk;
     int jmp;
     int addrCont = sqlite3WhereContinueLabel(pSubWInfo);
-    Table *pTab = pTabItem->pTab;
+    Table *pTab = pTabItem->pSTab;
     if( HasRowid(pTab) ){
       sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, -1, r);
       nPk = 1;
diff --git a/src/whereexpr.c b/src/whereexpr.c
index dcda75d264..766754828d 100644
--- a/src/whereexpr.c
+++ b/src/whereexpr.c
@@ -958,7 +958,7 @@ static Bitmask exprSelectUsage(WhereMaskSet *pMaskSet, Select *pS){
     if( ALWAYS(pSrc!=0) ){
       int i;
       for(i=0; i<pSrc->nSrc; i++){
-        mask |= exprSelectUsage(pMaskSet, pSrc->a[i].pSelect);
+        mask |= exprSelectUsage(pMaskSet, pSrc->a[i].sq.pSelect);
         if( pSrc->a[i].fg.isUsing==0 ){
           mask |= sqlite3WhereExprUsage(pMaskSet, pSrc->a[i].u3.pOn);
         }
@@ -996,7 +996,7 @@ static SQLITE_NOINLINE int exprMightBeIndexed2(
   int iCur;
   do{
     iCur = pFrom->a[j].iCursor;
-    for(pIdx=pFrom->a[j].pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    for(pIdx=pFrom->a[j].pSTab->pIndex; pIdx; pIdx=pIdx->pNext){
       if( pIdx->aColExpr==0 ) continue;
       for(i=0; i<pIdx->nKeyCol; i++){
         if( pIdx->aiColumn[i]!=XN_EXPR ) continue;
@@ -1040,7 +1040,7 @@ static int exprMightBeIndexed(
 
   for(i=0; i<pFrom->nSrc; i++){
     Index *pIdx;
-    for(pIdx=pFrom->a[i].pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    for(pIdx=pFrom->a[i].pSTab->pIndex; pIdx; pIdx=pIdx->pNext){
       if( pIdx->aColExpr ){
         return exprMightBeIndexed2(pFrom,aiCurCol,pExpr,i);
       }
@@ -1628,7 +1628,7 @@ void SQLITE_NOINLINE sqlite3WhereAddLimit(WhereClause *pWC, Select *p){
   assert( p!=0 && p->pLimit!=0 );                 /* 1 -- checked by caller */
   if( p->pGroupBy==0
    && (p->selFlags & (SF_Distinct|SF_Aggregate))==0             /* 2 */
-   && (p->pSrc->nSrc==1 && IsVirtual(p->pSrc->a[0].pTab))       /* 3 */
+   && (p->pSrc->nSrc==1 && IsVirtual(p->pSrc->a[0].pSTab))      /* 3 */
   ){
     ExprList *pOrderBy = p->pOrderBy;
     int iCsr = p->pSrc->a[0].iCursor;
@@ -1849,7 +1849,7 @@ void sqlite3WhereTabFuncArgs(
   Expr *pColRef;
   Expr *pTerm;
   if( pItem->fg.isTabFunc==0 ) return;
-  pTab = pItem->pTab;
+  pTab = pItem->pSTab;
   assert( pTab!=0 );
   pArgs = pItem->u1.pFuncArg;
   if( pArgs==0 ) return;
diff --git a/src/window.c b/src/window.c
index e5a78e37d2..9829d1740b 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1079,7 +1079,7 @@ int sqlite3WindowRewrite(Parse *pParse, Select *p){
                                      ** sqlite3SrcListAppend() */
     if( p->pSrc ){
       Table *pTab2;
-      p->pSrc->a[0].pSelect = pSub;
+      p->pSrc->a[0].sq.pSelect = pSub;
       p->pSrc->a[0].fg.isCorrelated = 1;
       sqlite3SrcListAssignCursors(pParse, p->pSrc);
       pSub->selFlags |= SF_Expanded|SF_OrderByReqd;
@@ -1093,7 +1093,7 @@ int sqlite3WindowRewrite(Parse *pParse, Select *p){
       }else{
         memcpy(pTab, pTab2, sizeof(Table));
         pTab->tabFlags |= TF_Ephemeral;
-        p->pSrc->a[0].pTab = pTab;
+        p->pSrc->a[0].pSTab = pTab;
         pTab = pTab2;
         memset(&w, 0, sizeof(w));
         w.xExprCallback = sqlite3WindowExtraAggFuncDepth;
@@ -1389,7 +1389,7 @@ int sqlite3WindowCompare(
 ** and initialize registers and cursors used by sqlite3WindowCodeStep().
 */
 void sqlite3WindowCodeInit(Parse *pParse, Select *pSelect){
-  int nEphExpr = pSelect->pSrc->a[0].pSelect->pEList->nExpr;
+  int nEphExpr = pSelect->pSrc->a[0].sq.pSelect->pEList->nExpr;
   Window *pMWin = pSelect->pWin;
   Window *pWin;
   Vdbe *v = sqlite3GetVdbe(pParse);
@@ -2789,7 +2789,7 @@ void sqlite3WindowCodeStep(
   Vdbe *v = sqlite3GetVdbe(pParse);
   int csrWrite;                   /* Cursor used to write to eph. table */
   int csrInput = p->pSrc->a[0].iCursor;     /* Cursor of sub-select */
-  int nInput = p->pSrc->a[0].pTab->nCol;    /* Number of cols returned by sub */
+  int nInput = p->pSrc->a[0].pSTab->nCol;   /* Number of cols returned by sub */
   int iInput;                               /* To iterate through sub cols */
   int addrNe;                     /* Address of OP_Ne */
   int addrGosubFlush = 0;         /* Address of OP_Gosub to flush: */

From 1521ca4c20c7ade39c671291b2214096c74cacd0 Mon Sep 17 00:00:00 2001
From: drh <>
Date: Mon, 19 Aug 2024 22:48:30 +0000
Subject: [PATCH 03/10] Refactor the SrcItem object so that information about
 subqueries is stored in a separately allocated Subquery object.  This reduces
 the memory requirements for SrcItem and makes the code run faster.  It also
 provides an expansion path for subquery processing that does not burden
 simple queries.  The current checking mostly works, but there are still
 issues that need to be tracked down and fixed.

FossilOrigin-Name: 8ff5dda8448d7e1a533d7f27db2573ce68fa9956b9d9847ced45e83c1f06bab0
---
 manifest        |  42 ++++++------
 manifest.uuid   |   2 +-
 src/alter.c     |  13 ++--
 src/attach.c    |   2 +-
 src/build.c     |  96 ++++++++++++++++++++++----
 src/expr.c      |  26 ++++---
 src/insert.c    |  71 +++++++++++--------
 src/parse.y     |  21 ++++--
 src/printf.c    |  13 ++--
 src/resolve.c   |  29 +++++---
 src/select.c    | 179 +++++++++++++++++++++++++++++-------------------
 src/sqliteInt.h |  40 ++++++++---
 src/treeview.c  |   8 +--
 src/walker.c    |   4 +-
 src/where.c     |  35 ++++++----
 src/wherecode.c |  20 ++++--
 src/whereexpr.c |   4 +-
 src/window.c    |  18 +++--
 18 files changed, 419 insertions(+), 204 deletions(-)

diff --git a/manifest b/manifest
index ef77b8894d..30b1edeab1 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Give\sunique\snames\sto\sfields\sin\sthe\sSrcItem\sobject,\sto\sfacilitate\sanalysis\sof\nhow\sthose\sfields\sare\sused\susing\s"grep".
-D 2024-08-17T23:23:23.271
+C Refactor\sthe\sSrcItem\sobject\sso\sthat\sinformation\sabout\ssubqueries\sis\sstored\nin\sa\sseparately\sallocated\sSubquery\sobject.\s\sThis\sreduces\sthe\smemory\srequirements\nfor\sSrcItem\sand\smakes\sthe\scode\srun\sfaster.\s\sIt\salso\sprovides\san\sexpansion\spath\nfor\ssubquery\sprocessing\sthat\sdoes\snot\sburden\ssimple\squeries.\s\sThe\scurrent\nchecking\smostly\sworks,\sbut\sthere\sare\sstill\sissues\sthat\sneed\sto\sbe\stracked\ndown\sand\sfixed.
+D 2024-08-19T22:48:30.539
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -692,9 +692,9 @@ F sqlite.pc.in 42b7bf0d02e08b9e77734a47798d1a55a9e0716b
 F sqlite3.1 acdff36db796e2d00225b911d3047d580cd136547298435426ce9d40347973cc
 F sqlite3.pc.in 48fed132e7cb71ab676105d2a4dc77127d8c1f3a
 F sqlite_cfg.h.in baf2e409c63d4e7a765e17769b6ff17c5a82bbd9cbf1e284fd2e4cefaff3fcf2
-F src/alter.c b73964bd6bc3122e884993c0666bae96d4e1e50a94b6f9008df32e6a18e99cd0
+F src/alter.c aa93e37e4a36a0525bbb2a2aeda20d2018f0aa995542c7dc658e031375e3f532
 F src/analyze.c 30bf40ec4208ead9e977bec017bccc8a9681820936e38ca5a4a7443100a6d5c5
-F src/attach.c d778bacb2ee5bc6a74c81a17376064e6a16ee447d82ee4ad1f7717a320d5a232
+F src/attach.c 08235ab62ed5ccc93c22bf36e640d19effcd632319615851bccf724ec9341333
 F src/auth.c 4c1ea890e0069ad73bead5d17a5b12c34cfa4f1a24175c8147ea439b64be271c
 F src/backup.c 5c97e8023aab1ce14a42387eb3ae00ba5a0644569e3476f38661fa6f824c3523
 F src/bitvec.c 9eac5f42c11914d5ef00a75605bb205e934f435c579687f985f1f8b0995c8645
@@ -702,7 +702,7 @@ F src/btmutex.c 79a43670447eacc651519a429f6ece9fd638563cf95b469d6891185ddae2b522
 F src/btree.c 8b42fc7d9efdb2df05c30e8f91ff6cfbd979724ae24bf90269028468b7a13333
 F src/btree.h 55066f513eb095db935169dab1dc2f7c7a747ef223c533f5d4ad4dfed346cbd0
 F src/btreeInt.h 98aadb6dcb77b012cab2574d6a728fad56b337fc946839b9898c4b4c969e30b6
-F src/build.c 664804cbefaf43c13fcb369474609cf8befa4d89933804dc276d0a15fbd66c34
+F src/build.c d243a17292e027c1d662e992fbd395123aacc4b74a4a9419d0b010088ba318dd
 F src/callback.c db3a45e376deff6a16c0058163fe0ae2b73a2945f3f408ca32cf74960b28d490
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 64e4b1227b4ed123146f0aa2989131d1fbd9b927b11e80c9d58c6a68f9cd5ce3
@@ -710,7 +710,7 @@ F src/date.c 13dd752847afb32ed70510ad7345a5b9c841f51ad904dba5d010f1fa3a6a324e
 F src/dbpage.c 80e46e1df623ec40486da7a5086cb723b0275a6e2a7b01d9f9b5da0f04ba2782
 F src/dbstat.c 3b677254d512fcafd4d0b341bf267b38b235ccfddbef24f9154e19360fa22e43
 F src/delete.c 8aaf9d05d6ff6349a7a6001cbf90c7a46b19b9f52ef2e47aa0415a529d5307a1
-F src/expr.c 835b637da89fe20a1ff90bd372904fd421ff92d1dfb9bbea9c81bbffbea46715
+F src/expr.c 6d5f2c38fe3ec06a7eac599dac822788b36064124e20112a844e9cd5156cb239
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 849049c74a4c68961154c124087b5c67d277217a2e642570d0c1bd6336859940
 F src/func.c 1f61e32e7a357e615b5d2e774bee563761fce4f2fd97ecb0f72c33e62a2ada5f
@@ -719,7 +719,7 @@ F src/hash.c 9ee4269fb1d6632a6fecfb9479c93a1f29271bddbbaf215dd60420bcb80c7220
 F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
 F src/hwtime.h f9c2dfb84dce7acf95ce6d289e46f5f9d3d1afd328e53da8f8e9008e3b3caae6
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
-F src/insert.c 2152b159ac214519e778b6996a85b9073ace054f5c9d430b375852e343a5ec92
+F src/insert.c b07865339e67869ff12d2eee3a1417f4779c742e2a51ae3d14ad45e5168f6f41
 F src/json.c 5b6a1d6015997b9ee848a32948720bdb26a0ef2de5a2127ebf7355ce66dbdc0d
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 7432c944ff197046d67a1207790a1b13eec4548c85a9457eb0896bb3641dfb36
@@ -749,23 +749,23 @@ F src/os_win.c 6ff43bac175bd9ed79e7c0f96840b139f2f51d01689a638fd05128becf94908a
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
 F src/pager.c b08600ebf0db90b6d1e9b8b6577c6fa3877cbe1a100bd0b2899e4c6e9adad4b3
 F src/pager.h 4b1140d691860de0be1347474c51fee07d5420bd7f802d38cbab8ea4ab9f538a
-F src/parse.y bc8df5d36afd06d50c1828072e4f3120d892af685436db3b8e776288803535e0
+F src/parse.y 967e0a712de8bee4b2cf82bd9efa36b68afd03cc486d4ea77a945feb49b057dc
 F src/pcache.c 588cc3c5ccaaadde689ed35ce5c5c891a1f7b1f4d1f56f6cf0143b74d8ee6484
 F src/pcache.h 1497ce1b823cf00094bb0cf3bac37b345937e6f910890c626b16512316d3abf5
 F src/pcache1.c 49516ad7718a3626f28f710fa7448ef1fce3c07fd169acbb4817341950264319
 F src/pragma.c 52bfbf6dfd668b69b5eb9bd1186e3a67367c8453807150d6e75239229924f684
 F src/pragma.h e690a356c18e98414d2e870ea791c1be1545a714ba623719deb63f7f226d8bb7
 F src/prepare.c d99931f45416652895e502328ca49fe782cfc4e1ebdcda13b3736d991ebf42ce
-F src/printf.c efa3973bdcacdbc8cf0ff3b3a58e16a105319eac8819823f5807579dc2fa4138
+F src/printf.c 17054fb94ffcf7a28362e9a5af4a0f813bd0c52200ae408eeebddc81feed9274
 F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
-F src/resolve.c d25fc99cd54d2acf4c655f942dd48ee60e3ada94d73c8b992487515f1295a3bc
+F src/resolve.c 9afed5fd7b9111633bdb74a73cdc47324e28e4dc6c27113e3e9aee38fb9422ab
 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97
-F src/select.c 10ff02352f4c6eb7bc8d5711f0f74199b94ae9adc346f10391931f5c55d1c68f
+F src/select.c 3e284895745f57de3b37b17fce9eb0e26bc54fccc94ea1ff5342be4360e3674b
 F src/shell.c.in 94571558b0fb28c37a5cf6dbd6ea27285341023a28a8cb5795cd2768fab67704
 F src/sqlite.h.in 1ad9110150773c38ebababbad11b5cb361bcd3997676dec1c91ac5e0416a7b86
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 3f046c04ea3595d6bfda99b781926b17e672fd6d27da2ba6d8d8fc39981dcb54
-F src/sqliteInt.h 95186ebaf79560fa44b1a05bd7b4b14846e037a285177ca65082a9ae952a6c29
+F src/sqliteInt.h 630e356b7d94df1dcbc32d4f7d4569725a12c6de014fe064311219c22d9cbd54
 F src/sqliteLimit.h 6878ab64bdeb8c24a1d762d45635e34b96da21132179023338c93f820eee6728
 F src/status.c cb11f8589a6912af2da3bb1ec509a94dd8ef27df4d4c1a97e0bcf2309ece972b
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -824,7 +824,7 @@ F src/test_window.c 6d80e11fba89a1796525e6f0048ff0c7789aa2c6b0b11c80827dc1437bd8
 F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
 F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
 F src/tokenize.c 3f703cacdab728d7741e5a6ac242006d74fe1c2754d4f03ed889d7253259bd68
-F src/treeview.c a337ab329f94e627c9a5efee0326d3359e352c4f0c0bb5c8f4b686fe03e6e7e8
+F src/treeview.c e98dbc8068d27f3d0bd2a4cebfce6a7c21c776edc23d80e12c67a70cd2ba3fe5
 F src/trigger.c 68d849ea6ccab67beb450d1a0d065c6118f0884a779388b07f0d9a27dbda38c9
 F src/update.c 0e01aa6a3edf9ec112b33eb714b9016a81241497b1fb7c3e74332f4f71756508
 F src/upsert.c 215328c3f91623c520ec8672c44323553f12caeb4f01b1090ebdca99fdf7b4f1
@@ -845,12 +845,12 @@ F src/vtab.c 5fb499d20494b7eecaadb7584634af9afcb374cb0524912b475fcb1712458a1b
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 887fc4ca3f020ebb2e376f222069570834ac63bf50111ef0cbf3ae417048ed89
 F src/wal.h ba252daaa94f889f4b2c17c027e823d9be47ce39da1d3799886bbd51f0490452
-F src/walker.c e5898234c5920481d962e29b96ecf403b992b12ae243ad0e53659386a1b3e554
-F src/where.c d0140395a35fbc451e9d07c9816895d399f02ae76cbcd255e8ce1069548b02c8
+F src/walker.c d5006d6b005e4ea7302ad390957a8d41ed83faa177e412f89bc5600a7462a014
+F src/where.c b6f79b189fcba459bb80420d3b4102f42a399be36ff29a3deff4ae4888fee46d
 F src/whereInt.h 6444b888ce395cb80511284b8a73b63472d34247fcb1b125ee06a54fa6ae878e
-F src/wherecode.c 3e130abafc185a29c8dbdcc33e6150dff2aa884f75483e159feef170961af65d
-F src/whereexpr.c 784f641ba3d6f1fdb4f65e3891daa50067a4c51f1acd11b461397f7d4c622907
-F src/window.c ffbf65ba62ce329e2fd68b35f11e920121fac45dab0f9a4bbc486125ccc98b6c
+F src/wherecode.c 137797b0de9ddf1ff43e5b0edffcc76fb05184ed651fc4f5a0a01a45c0b89d04
+F src/whereexpr.c 6a72cf607548765a262f216e87373fd675a4646f9cc4278fc519b66cf03dbc13
+F src/window.c 499d48f315a09242dc68f2fac635ed27dcf6bbb0d9ab9084857898c64489e975
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/affinity2.test ce1aafc86e110685b324e9a763eab4f2a73f737842ec3b687bd965867de90627
 F test/affinity3.test f094773025eddf31135c7ad4cde722b7696f8eb07b97511f98585addf2a510a9
@@ -2205,8 +2205,8 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P a4c59ac3c6ec979c25b544d29e47b8e39f6439c098eed8f84b3bd506c9adf047
-R 1d81e98efd997ac91c2ceea4c803b7e6
+P 9f5aeef3cbc2c95267c8f7bf60d5c66971a76789669fb0e8f853273ff6f616f2
+R 0dac77664f5c62d0dcc882ea3148d6f4
 U drh
-Z 8ec986f4842c563a443c2f1a23450bf4
+Z a11cd0d49c593b1144d9510fd31aa2a7
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 0e51ef0919..ca5d536722 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-9f5aeef3cbc2c95267c8f7bf60d5c66971a76789669fb0e8f853273ff6f616f2
+8ff5dda8448d7e1a533d7f27db2573ce68fa9956b9d9847ced45e83c1f06bab0
diff --git a/src/alter.c b/src/alter.c
index 41146f54e9..ff20757589 100644
--- a/src/alter.c
+++ b/src/alter.c
@@ -1366,8 +1366,9 @@ static int renameResolveTrigger(Parse *pParse){
           int i;
           for(i=0; i<pStep->pFrom->nSrc && rc==SQLITE_OK; i++){
             SrcItem *p = &pStep->pFrom->a[i];
-            if( p->sq.pSelect ){
-              sqlite3SelectPrep(pParse, p->sq.pSelect, 0);
+            if( p->fg.isSubquery ){
+              assert( p->u4.pSubq!=0 );
+              sqlite3SelectPrep(pParse, p->u4.pSubq->pSelect, 0);
             }
           }
         }
@@ -1435,8 +1436,12 @@ static void renameWalkTrigger(Walker *pWalker, Trigger *pTrigger){
     }
     if( pStep->pFrom ){
       int i;
-      for(i=0; i<pStep->pFrom->nSrc; i++){
-        sqlite3WalkSelect(pWalker, pStep->pFrom->a[i].sq.pSelect);
+      SrcList *pFrom = pStep->pFrom;
+      for(i=0; i<pFrom->nSrc; i++){
+        if( pFrom->a[i].fg.isSubquery ){
+          assert( pFrom->a[i].u4.pSubq!=0 );
+          sqlite3WalkSelect(pWalker, pFrom->a[i].u4.pSubq->pSelect);
+        }
       }
     }
   }
diff --git a/src/attach.c b/src/attach.c
index 65b492474e..76476685fb 100644
--- a/src/attach.c
+++ b/src/attach.c
@@ -479,7 +479,7 @@ static int fixSelectCb(Walker *p, Select *pSelect){
 
   if( NEVER(pList==0) ) return WRC_Continue;
   for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
-    if( pFix->bTemp==0 ){
+    if( pFix->bTemp==0 && pItem->fg.isSubquery==0 ){
       if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
         if( iDb!=sqlite3FindDbName(db, pItem->u4.zDatabase) ){
           sqlite3ErrorMsg(pFix->pParse,
diff --git a/src/build.c b/src/build.c
index ff798087af..b585c19719 100644
--- a/src/build.c
+++ b/src/build.c
@@ -4914,13 +4914,40 @@ void sqlite3SrcListAssignCursors(Parse *pParse, SrcList *pList){
     for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
       if( pItem->iCursor>=0 ) continue;
       pItem->iCursor = pParse->nTab++;
-      if( pItem->sq.pSelect ){
-        sqlite3SrcListAssignCursors(pParse, pItem->sq.pSelect->pSrc);
+      if( pItem->fg.isSubquery ){
+        assert( pItem->u4.pSubq!=0 );
+        assert( pItem->u4.pSubq->pSelect!=0 );
+        assert( pItem->u4.pSubq->pSelect->pSrc!=0 );
+        sqlite3SrcListAssignCursors(pParse, pItem->u4.pSubq->pSelect->pSrc);
       }
     }
   }
 }
 
+/*
+** Delete a Subquery object and its substructure.
+*/
+void sqlite3SubqueryDelete(sqlite3 *db, Subquery *pSubq){
+  assert( pSubq!=0 && pSubq->pSelect!=0 );
+  sqlite3SelectDelete(db, pSubq->pSelect);
+  sqlite3DbFree(db, pSubq);
+}
+
+/*
+** Remove a Subquery from a SrcItem.  Return the associated Select object.
+** The returned Select becomes the responsibility of the caller.
+*/
+Select *sqlite3SubqueryDetach(sqlite3 *db, SrcItem *pItem){
+  Select *pSel;
+  assert( pItem!=0 );
+  assert( pItem->fg.isSubquery );
+  pSel = pItem->u4.pSubq->pSelect;
+  sqlite3DbFree(db, pItem->u4.pSubq);
+  pItem->u4.pSubq = 0;
+  pItem->fg.isSubquery = 0;
+  return pSel;
+}
+
 /*
 ** Delete an entire SrcList including all its substructure.
 */
@@ -4932,22 +4959,19 @@ void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
   for(pItem=pList->a, i=0; i<pList->nSrc; i++, pItem++){
  
     /* Check invariants on SrcItem */
-    assert( pItem->sq.pSelect==0
-         || (pItem->sq.pSelect->selFlags & SF_MultiValue)==0
-         || (pItem->fg.hadSchema==0
-              && (pItem->fg.fixedSchema || pItem->u4.zDatabase==0)) );
+    assert( !pItem->fg.hadSchema || !pItem->fg.isSubquery );
     assert( pItem->fg.hadSchema==0 || pItem->fg.fixedSchema==1 );
 
-
     if( pItem->zName ) sqlite3DbNNFreeNN(db, pItem->zName);
     if( pItem->zAlias ) sqlite3DbNNFreeNN(db, pItem->zAlias);
-    if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+    if( pItem->fg.isSubquery ){
+      sqlite3SubqueryDelete(db, pItem->u4.pSubq);
+    }else if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
       sqlite3DbNNFreeNN(db, pItem->u4.zDatabase);
     }
     if( pItem->fg.isIndexedBy ) sqlite3DbFree(db, pItem->u1.zIndexedBy);
     if( pItem->fg.isTabFunc ) sqlite3ExprListDelete(db, pItem->u1.pFuncArg);
     sqlite3DeleteTable(db, pItem->pSTab);
-    if( pItem->sq.pSelect ) sqlite3SelectDelete(db, pItem->sq.pSelect);
     if( pItem->fg.isUsing ){
       sqlite3IdListDelete(db, pItem->u3.pUsing);
     }else if( pItem->u3.pOn ){
@@ -4957,6 +4981,52 @@ void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
   sqlite3DbNNFreeNN(db, pList);
 }
 
+/*
+** Attach a Subquery object to pItem->uv.pSubq.  Set the
+** pSelect value but leave all the other values initialized
+** to zero.
+**
+** A copy of the Select object is made if dupSelect is true, and the
+** SrcItem takes responsibility for deleting the copy.  If dupSelect is
+** false, ownership of the Select passes to the SrcItem.  Either way,
+** the SrcItem will take responsibility for deleting the Select.
+**
+** When dupSelect is zero, that means the Select might get deleted right
+** away if there is an OOM error.  Beware.
+**
+** Return non-zero on success.  Return zero on an OOM error.
+*/
+int sqlite3SrcItemAttachSubquery(
+  Parse *pParse,     /* Parsing context */
+  SrcItem *pItem,    /* Item to which the subquery is to be attached */
+  Select *pSelect,   /* The subquery SELECT.  Must be non-NULL */
+  int dupSelect      /* If true, attach a copy of pSelect, not pSelect itself.*/
+){
+  Subquery *p;
+  if( pSelect==0 ) return SQLITE_OK;
+  assert( pItem->fg.isSubquery==0 );
+  if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+    sqlite3DbFree(pParse->db, pItem->u4.zDatabase);
+    pItem->u4.zDatabase = 0;
+  }
+  pItem->fg.fixedSchema = 0;
+  if( dupSelect ){
+    pSelect = sqlite3SelectDup(pParse->db, pSelect, 0);
+    if( pSelect==0 ) return 0;
+  }
+  p = pItem->u4.pSubq = sqlite3DbMallocRawNN(pParse->db, sizeof(Subquery));
+  if( p==0 ){
+    sqlite3SelectDelete(pParse->db, pSelect);
+    return 0;
+  }
+  pItem->fg.isSubquery = 1;
+  p->pSelect = pSelect;
+  assert( offsetof(Subquery, pSelect)==0 );
+  memset(((char*)p)+sizeof(p->pSelect), 0, sizeof(*p)-sizeof(p->pSelect));
+  return 1;
+}
+
+
 /*
 ** This routine is called by the parser to add a new term to the
 ** end of a growing FROM clause.  The "p" parameter is the part of
@@ -5006,10 +5076,12 @@ SrcList *sqlite3SrcListAppendFromTerm(
   if( pAlias->n ){
     pItem->zAlias = sqlite3NameFromToken(db, pAlias);
   }
+  assert( pSubquery==0 || pDatabase==0 );
   if( pSubquery ){
-    pItem->sq.pSelect = pSubquery;
-    if( pSubquery->selFlags & SF_NestedFrom ){
-      pItem->fg.isNestedFrom = 1;
+    if( sqlite3SrcItemAttachSubquery(pParse, pItem, pSubquery, 0) ){
+      if( pSubquery->selFlags & SF_NestedFrom ){
+        pItem->fg.isNestedFrom = 1;
+      }
     }
   }
   assert( pOnUsing==0 || pOnUsing->pOn==0 || pOnUsing->pUsing==0 );
diff --git a/src/expr.c b/src/expr.c
index 6ad789a3d8..1b18828dd6 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1877,18 +1877,30 @@ SrcList *sqlite3SrcListDup(sqlite3 *db, const SrcList *p, int flags){
     SrcItem *pNewItem = &pNew->a[i];
     const SrcItem *pOldItem = &p->a[i];
     Table *pTab;
-    if( pOldItem->fg.fixedSchema ){
+    pNewItem->fg = pOldItem->fg;
+    if( pOldItem->fg.isSubquery ){
+      Subquery *pNewSubq = sqlite3DbMallocRaw(db, sizeof(Subquery));
+      if( pNewSubq==0 ){
+        assert( db->mallocFailed );
+        pNewItem->fg.isSubquery = 0;
+      }else{
+        memcpy(pNewSubq, pOldItem->u4.pSubq, sizeof(*pNewSubq));
+        pNewSubq->pSelect = sqlite3SelectDup(db, pNewSubq->pSelect, flags);
+        if( pNewSubq->pSelect==0 ){
+          sqlite3DbFree(db, pNewSubq);
+          pNewSubq = 0;
+          pNewItem->fg.isSubquery = 0;
+        }
+      }
+      pNewItem->u4.pSubq = pNewSubq;
+    }else if( pOldItem->fg.fixedSchema ){
       pNewItem->u4.pSchema = pOldItem->u4.pSchema;
     }else{
       pNewItem->u4.zDatabase = sqlite3DbStrDup(db, pOldItem->u4.zDatabase);
     }
     pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
     pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
-    pNewItem->fg = pOldItem->fg;
     pNewItem->iCursor = pOldItem->iCursor;
-    pNewItem->sq.addrFillSub = pOldItem->sq.addrFillSub;
-    pNewItem->sq.regReturn = pOldItem->sq.regReturn;
-    pNewItem->sq.regResult = pOldItem->sq.regResult;
     if( pNewItem->fg.isIndexedBy ){
       pNewItem->u1.zIndexedBy = sqlite3DbStrDup(db, pOldItem->u1.zIndexedBy);
     }else if( pNewItem->fg.isTabFunc ){
@@ -1905,7 +1917,6 @@ SrcList *sqlite3SrcListDup(sqlite3 *db, const SrcList *p, int flags){
     if( pTab ){
       pTab->nTabRef++;
     }
-    pNewItem->sq.pSelect = sqlite3SelectDup(db, pOldItem->sq.pSelect, flags);
     if( pOldItem->fg.isUsing ){
       assert( pNewItem->fg.isUsing );
       pNewItem->u3.pUsing = sqlite3IdListDup(db, pOldItem->u3.pUsing);
@@ -1979,7 +1990,6 @@ Select *sqlite3SelectDup(sqlite3 *db, const Select *pDup, int flags){
     pp = &pNew->pPrior;
     pNext = pNew;
   }
-
   return pRet;
 }
 #else
@@ -2999,7 +3009,7 @@ static Select *isCandidateForInOpt(const Expr *pX){
   pSrc = p->pSrc;
   assert( pSrc!=0 );
   if( pSrc->nSrc!=1 ) return 0;          /* Single term in FROM clause */
-  if( pSrc->a[0].sq.pSelect ) return 0;  /* FROM is not a subquery or view */
+  if( pSrc->a[0].fg.isSubquery) return 0;/* FROM is not a subquery or view */
   pTab = pSrc->a[0].pSTab;
   assert( pTab!=0 );
   assert( !IsView(pTab)  );              /* FROM clause is not a view */
diff --git a/src/insert.c b/src/insert.c
index 4447cdc22e..d65ead2a0b 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -585,8 +585,9 @@ void sqlite3AutoincrementEnd(Parse *pParse){
 void sqlite3MultiValuesEnd(Parse *pParse, Select *pVal){
   if( ALWAYS(pVal) && pVal->pSrc->nSrc>0 ){
     SrcItem *pItem = &pVal->pSrc->a[0];
-    sqlite3VdbeEndCoroutine(pParse->pVdbe, pItem->sq.regReturn);
-    sqlite3VdbeJumpHere(pParse->pVdbe, pItem->sq.addrFillSub - 1);
+    assert( pItem->fg.isSubquery && pItem->u4.pSubq!=0 );
+    sqlite3VdbeEndCoroutine(pParse->pVdbe, pItem->u4.pSubq->regReturn);
+    sqlite3VdbeJumpHere(pParse->pVdbe, pItem->u4.pSubq->addrFillSub - 1);
   }
 }
 
@@ -714,6 +715,7 @@ Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow){
 
       if( pRet ){
         SelectDest dest;
+        Subquery *pSubq;
         pRet->pSrc->nSrc = 1;
         pRet->pPrior = pLeft->pPrior;
         pRet->op = pLeft->op;
@@ -723,29 +725,31 @@ Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow){
         assert( pLeft->pNext==0 );
         assert( pRet->pNext==0 );
         p = &pRet->pSrc->a[0];
-        p->sq.pSelect = pLeft;
         p->fg.viaCoroutine = 1;
-        p->sq.addrFillSub = sqlite3VdbeCurrentAddr(v) + 1;
-        p->sq.regReturn = ++pParse->nMem;
         p->iCursor = -1;
         p->u1.nRow = 2;
-        sqlite3VdbeAddOp3(v, OP_InitCoroutine,
-                          p->sq.regReturn, 0, p->sq.addrFillSub);
-        sqlite3SelectDestInit(&dest, SRT_Coroutine, p->sq.regReturn);
+        if( sqlite3SrcItemAttachSubquery(pParse, p, pLeft, 0) ){
+          pSubq = p->u4.pSubq;
+          pSubq->addrFillSub = sqlite3VdbeCurrentAddr(v) + 1;
+          pSubq->regReturn = ++pParse->nMem;
+          sqlite3VdbeAddOp3(v, OP_InitCoroutine,
+                            pSubq->regReturn, 0, pSubq->addrFillSub);
+          sqlite3SelectDestInit(&dest, SRT_Coroutine, pSubq->regReturn);
 
-        /* Allocate registers for the output of the co-routine. Do so so
-        ** that there are two unused registers immediately before those
-        ** used by the co-routine. This allows the code in sqlite3Insert()
-        ** to use these registers directly, instead of copying the output
-        ** of the co-routine to a separate array for processing.  */
-        dest.iSdst = pParse->nMem + 3; 
-        dest.nSdst = pLeft->pEList->nExpr;
-        pParse->nMem += 2 + dest.nSdst;
+          /* Allocate registers for the output of the co-routine. Do so so
+          ** that there are two unused registers immediately before those
+          ** used by the co-routine. This allows the code in sqlite3Insert()
+          ** to use these registers directly, instead of copying the output
+          ** of the co-routine to a separate array for processing.  */
+          dest.iSdst = pParse->nMem + 3; 
+          dest.nSdst = pLeft->pEList->nExpr;
+          pParse->nMem += 2 + dest.nSdst;
 
-        pLeft->selFlags |= SF_MultiValue;
-        sqlite3Select(pParse, pLeft, &dest);
-        p->sq.regResult = dest.iSdst;
-        assert( pParse->nErr || dest.iSdst>0 );
+          pLeft->selFlags |= SF_MultiValue;
+          sqlite3Select(pParse, pLeft, &dest);
+          pSubq->regResult = dest.iSdst;
+          assert( pParse->nErr || dest.iSdst>0 );
+        }
         pLeft = pRet;
       }
     }else{
@@ -755,12 +759,18 @@ Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow){
     }
   
     if( pParse->nErr==0 ){
+      Subquery *pSubq;
       assert( p!=0 );
-      if( p->sq.pSelect->pEList->nExpr!=pRow->nExpr ){
-        sqlite3SelectWrongNumTermsError(pParse, p->sq.pSelect);
+      assert( p->fg.isSubquery );
+      pSubq = p->u4.pSubq;
+      assert( pSubq!=0 );
+      assert( pSubq->pSelect!=0 );
+      assert( pSubq->pSelect->pEList!=0 );
+      if( pSubq->pSelect->pEList->nExpr!=pRow->nExpr ){
+        sqlite3SelectWrongNumTermsError(pParse, pSubq->pSelect);
       }else{
-        sqlite3ExprCodeExprList(pParse, pRow, p->sq.regResult, 0, 0);
-        sqlite3VdbeAddOp1(pParse->pVdbe, OP_Yield, p->sq.regReturn);
+        sqlite3ExprCodeExprList(pParse, pRow, pSubq->regResult, 0, 0);
+        sqlite3VdbeAddOp1(pParse->pVdbe, OP_Yield, pSubq->regReturn);
       }
     }
     sqlite3ExprListDelete(pParse->db, pRow);
@@ -1111,9 +1121,14 @@ void sqlite3Insert(
      && pSelect->pPrior==0
     ){
       SrcItem *pItem = &pSelect->pSrc->a[0];
-      dest.iSDParm = pItem->sq.regReturn;
-      regFromSelect = pItem->sq.regResult;
-      nColumn = pItem->sq.pSelect->pEList->nExpr;
+      Subquery *pSubq;
+      assert( pItem->fg.isSubquery );
+      pSubq = pItem->u4.pSubq;
+      dest.iSDParm = pSubq->regReturn;
+      regFromSelect = pSubq->regResult;
+      assert( pSubq->pSelect!=0 );
+      assert( pSubq->pSelect->pEList!=0 );
+      nColumn = pSubq->pSelect->pEList->nExpr;
       ExplainQueryPlan((pParse, 0, "SCAN %S", pItem));
       if( bIdListInOrder && nColumn==pTab->nCol ){
         regData = regFromSelect;
@@ -3033,7 +3048,7 @@ static int xferOptimization(
   if( pSelect->pSrc->nSrc!=1 ){
     return 0;   /* FROM clause must have exactly one term */
   }
-  if( pSelect->pSrc->a[0].sq.pSelect ){
+  if( pSelect->pSrc->a[0].fg.isSubquery ){
     return 0;   /* FROM clause cannot contain a subquery */
   }
   if( pSelect->pWhere ){
diff --git a/src/parse.y b/src/parse.y
index 9e656d0bc7..a47c587547 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -742,10 +742,20 @@ seltablist(A) ::= stl_prefix(A) nm(Y) dbnm(D) LP exprlist(E) RP as(Z) on_using(N
         SrcItem *pOld = F->a;
         assert( pOld->fg.fixedSchema==0 );
         pNew->zName = pOld->zName;
-        pNew->u4.zDatabase = pOld->u4.zDatabase;
-        pNew->sq.pSelect = pOld->sq.pSelect;
-        if( pNew->sq.pSelect && (pNew->sq.pSelect->selFlags & SF_NestedFrom)!=0 ){
-          pNew->fg.isNestedFrom = 1;
+        assert( pOld->fg.fixedSchema==0 );
+        if( pOld->fg.isSubquery ){
+          pNew->fg.isSubquery = 1;
+          pNew->u4.pSubq = pOld->u4.pSubq;
+          pOld->u4.pSubq = 0;
+          pOld->fg.isSubquery = 0;
+          if( pNew->u4.pSubq->pSelect
+           && (pNew->u4.pSubq->pSelect->selFlags & SF_NestedFrom)!=0
+          ){
+            pNew->fg.isNestedFrom = 1;
+          }
+        }else{
+          pNew->u4.zDatabase = pOld->u4.zDatabase;
+          pOld->u4.zDatabase = 0;
         }
         if( pOld->fg.isTabFunc ){
           pNew->u1.pFuncArg = pOld->u1.pFuncArg;
@@ -753,8 +763,7 @@ seltablist(A) ::= stl_prefix(A) nm(Y) dbnm(D) LP exprlist(E) RP as(Z) on_using(N
           pOld->fg.isTabFunc = 0;
           pNew->fg.isTabFunc = 1;
         }
-        pOld->zName = pOld->u4.zDatabase = 0;
-        pOld->sq.pSelect = 0;
+        pOld->zName = 0;
       }
       sqlite3SrcListDelete(pParse->db, F);
     }else{
diff --git a/src/printf.c b/src/printf.c
index 027905d26f..be7ffc8c76 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -848,16 +848,19 @@ void sqlite3_str_vappendf(
         if( pItem->zAlias && !flag_altform2 ){
           sqlite3_str_appendall(pAccum, pItem->zAlias);
         }else if( pItem->zName ){
-          if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+          if( pItem->fg.fixedSchema==0
+           && pItem->fg.isSubquery==0
+           && pItem->u4.zDatabase!=0
+          ){
             sqlite3_str_appendall(pAccum, pItem->u4.zDatabase);
             sqlite3_str_append(pAccum, ".", 1);
           }
           sqlite3_str_appendall(pAccum, pItem->zName);
         }else if( pItem->zAlias ){
           sqlite3_str_appendall(pAccum, pItem->zAlias);
-        }else{
-          Select *pSel = pItem->sq.pSelect;
-          assert( pSel!=0 ); /* Because of tag-20240424-1 */
+        }else if( pItem->fg.isSubquery ){/* Because of tag-20240424-1 */
+          Select *pSel = pItem->u4.pSubq->pSelect;
+          assert( pSel!=0 ); 
           if( pSel->selFlags & SF_NestedFrom ){
             sqlite3_str_appendf(pAccum, "(join-%u)", pSel->selId);
           }else if( pSel->selFlags & SF_MultiValue ){
@@ -867,6 +870,8 @@ void sqlite3_str_vappendf(
           }else{
             sqlite3_str_appendf(pAccum, "(subquery-%u)", pSel->selId);
           }
+        }else{
+          sqlite3_str_appendf(pAccum, "(unknown-data-source-%p)", pItem);
         }
         length = width = 0;
         break;
diff --git a/src/resolve.c b/src/resolve.c
index 02a48d6993..6dcb4e7322 100644
--- a/src/resolve.c
+++ b/src/resolve.c
@@ -349,7 +349,7 @@ static int lookupName(
         pTab = pItem->pSTab;
         assert( pTab!=0 && pTab->zName!=0 );
         assert( pTab->nCol>0 || pParse->nErr );
-        assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->sq.pSelect));
+        assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem));
         if( pItem->fg.isNestedFrom ){
           /* In this case, pItem is a subquery that has been formed from a
           ** parenthesized subset of the FROM clause terms.  Example:
@@ -358,8 +358,12 @@ static int lookupName(
           **             This pItem -------------^
           */
           int hit = 0;
-          assert( pItem->sq.pSelect!=0 );
-          pEList = pItem->sq.pSelect->pEList;
+          Select *pSel;
+          assert( pItem->fg.isSubquery );
+          assert( pItem->u4.pSubq!=0 );
+          pSel = pItem->u4.pSubq->pSelect;
+          assert( pSel!=0 );
+          pEList = pSel->pEList;
           assert( pEList!=0 );
           assert( pEList->nExpr==pTab->nCol );
           for(j=0; j<pEList->nExpr; j++){
@@ -1880,7 +1884,11 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
     ** moves the pOrderBy down to the sub-query. It will be moved back
     ** after the names have been resolved.  */
     if( p->selFlags & SF_Converted ){
-      Select *pSub = p->pSrc->a[0].sq.pSelect;
+      Select *pSub;
+      assert( p->pSrc->a[0].fg.isSubquery );
+      assert( p->pSrc->a[0].u4.pSubq!=0 );
+      pSub = p->pSrc->a[0].u4.pSubq->pSelect;
+      assert( pSub!=0 );
       assert( p->pSrc->nSrc==1 && p->pOrderBy );
       assert( pSub->pPrior && pSub->pOrderBy==0 );
       pSub->pOrderBy = p->pOrderBy;
@@ -1893,13 +1901,15 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
     for(i=0; i<p->pSrc->nSrc; i++){
       SrcItem *pItem = &p->pSrc->a[i];
       assert( pItem->zName!=0
-              || pItem->sq.pSelect!=0 );  /* Test of tag-20240424-1*/
-      if( pItem->sq.pSelect && (pItem->sq.pSelect->selFlags & SF_Resolved)==0 ){
+              || pItem->fg.isSubquery );  /* Test of tag-20240424-1*/
+      if( pItem->fg.isSubquery
+       && (pItem->u4.pSubq->pSelect->selFlags & SF_Resolved)==0
+      ){
         int nRef = pOuterNC ? pOuterNC->nRef : 0;
         const char *zSavedContext = pParse->zAuthContext;
 
         if( pItem->zName ) pParse->zAuthContext = pItem->zName;
-        sqlite3ResolveSelectNames(pParse, pItem->sq.pSelect, pOuterNC);
+        sqlite3ResolveSelectNames(pParse, pItem->u4.pSubq->pSelect, pOuterNC);
         pParse->zAuthContext = zSavedContext;
         if( pParse->nErr ) return WRC_Abort;
         assert( db->mallocFailed==0 );
@@ -2001,7 +2011,10 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
     ** These integers will be replaced by copies of the corresponding result
     ** set expressions by the call to resolveOrderGroupBy() below.  */
     if( p->selFlags & SF_Converted ){
-      Select *pSub = p->pSrc->a[0].sq.pSelect;
+      Select *pSub;
+      assert( p->pSrc->a[0].fg.isSubquery );
+      pSub = p->pSrc->a[0].u4.pSubq->pSelect;
+      assert( pSub!=0 );
       p->pOrderBy = pSub->pOrderBy;
       pSub->pOrderBy = 0;
     }
diff --git a/src/select.c b/src/select.c
index 5f55b402cf..8bddc03bb4 100644
--- a/src/select.c
+++ b/src/select.c
@@ -332,11 +332,13 @@ int sqlite3ColumnIndex(Table *pTab, const char *zCol){
 */
 void sqlite3SrcItemColumnUsed(SrcItem *pItem, int iCol){
   assert( pItem!=0 );
-  assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->sq.pSelect) );
+  assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem) );
   if( pItem->fg.isNestedFrom ){
     ExprList *pResults;
-    assert( pItem->sq.pSelect!=0 );
-    pResults = pItem->sq.pSelect->pEList;
+    assert( pItem->fg.isSubquery );
+    assert( pItem->u4.pSubq!=0 );
+    assert( pItem->u4.pSubq->pSelect!=0 );
+    pResults = pItem->u4.pSubq->pSelect->pEList;
     assert( pResults!=0 );
     assert( iCol>=0 && iCol<pResults->nExpr );
     pResults->a[iCol].fg.bUsed = 1;
@@ -1931,7 +1933,11 @@ static const char *columnTypeImpl(
         for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
         if( j<pTabList->nSrc ){
           pTab = pTabList->a[j].pSTab;
-          pS = pTabList->a[j].sq.pSelect;
+          if( pTabList->a[j].fg.isSubquery ){
+            pS = pTabList->a[j].u4.pSubq->pSelect;
+          }else{
+            pS = 0;
+          }
         }else{
           pNC = pNC->pNext;
         }
@@ -3983,7 +3989,9 @@ static void substSelect(
     pSrc = p->pSrc;
     assert( pSrc!=0 );
     for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
-      substSelect(pSubst, pItem->sq.pSelect, 1);
+      if( pItem->fg.isSubquery ){
+        substSelect(pSubst, pItem->u4.pSubq->pSelect, 1);
+      }
       if( pItem->fg.isTabFunc ){
         substExprList(pSubst, pItem->u1.pFuncArg);
       }
@@ -4054,8 +4062,10 @@ static void srclistRenumberCursors(
         aCsrMap[pItem->iCursor+1] = pParse->nTab++;
       }
       pItem->iCursor = aCsrMap[pItem->iCursor+1];
-      for(p=pItem->sq.pSelect; p; p=p->pPrior){
-        srclistRenumberCursors(pParse, aCsrMap, p->pSrc, -1);
+      if( pItem->fg.isSubquery ){
+        for(p=pItem->u4.pSubq->pSelect; p; p=p->pPrior){
+          srclistRenumberCursors(pParse, aCsrMap, p->pSrc, -1);
+        }
       }
     }
   }
@@ -4366,7 +4376,8 @@ static int flattenSubquery(
   assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
   pSubitem = &pSrc->a[iFrom];
   iParent = pSubitem->iCursor;
-  pSub = pSubitem->sq.pSelect;
+  assert( pSubitem->fg.isSubquery );
+  pSub = pSubitem->u4.pSubq->pSelect;
   assert( pSub!=0 );
 
 #ifndef SQLITE_OMIT_WINDOWFUNC
@@ -4505,7 +4516,12 @@ static int flattenSubquery(
   pParse->zAuthContext = zSavedAuthContext;
 
   /* Delete the transient structures associated with the subquery */
-  pSub1 = pSubitem->sq.pSelect;
+  
+  if( ALWAYS(pSubitem->fg.isSubquery) ){
+    pSub1 = sqlite3SubqueryDetach(db, pSubitem);
+  }else{
+    pSub1 = 0;
+  }
   if( pSubitem->fg.fixedSchema==0 ){
     sqlite3DbFree(db, pSubitem->u4.zDatabase);
     pSubitem->u4.zDatabase = 0;
@@ -4514,7 +4530,6 @@ static int flattenSubquery(
   sqlite3DbFree(db, pSubitem->zAlias);
   pSubitem->zName = 0;
   pSubitem->zAlias = 0;
-  pSubitem->sq.pSelect = 0;
   assert( pSubitem->fg.isUsing!=0 || pSubitem->u3.pOn==0 );
 
   /* If the sub-query is a compound SELECT statement, then (by restrictions
@@ -4579,11 +4594,14 @@ static int flattenSubquery(
       TREETRACE(0x4,pParse,p,("compound-subquery flattener"
                               " creates %u as peer\n",pNew->selId));
     }
-    assert( pSubitem->sq.pSelect==0 );
+    assert( pSubitem->fg.isSubquery==0 );
   }
   sqlite3DbFree(db, aCsrMap);
   if( db->mallocFailed ){
-    pSubitem->sq.pSelect = pSub1;
+    assert( pSubitem->fg.fixedSchema==0 );
+    assert( pSubitem->fg.isSubquery==0 );
+    assert( pSubitem->u4.zDatabase==0 );
+    sqlite3SrcItemAttachSubquery(pParse, pSubitem, pSub1, 0);
     return 1;
   }
 
@@ -4659,8 +4677,11 @@ static int flattenSubquery(
     */
     for(i=0; i<nSubSrc; i++){
       SrcItem *pItem = &pSrc->a[i+iFrom];
-      if( pItem->fg.isUsing ) sqlite3IdListDelete(db, pItem->u3.pUsing);
       assert( pItem->fg.isTabFunc==0 );
+      assert( pItem->fg.isSubquery
+           || pItem->fg.fixedSchema
+           || pItem->u4.zDatabase==0 );
+      if( pItem->fg.isUsing ) sqlite3IdListDelete(db, pItem->u3.pUsing);
       *pItem = pSubSrc->a[i];
       pItem->fg.jointype |= ltorj;
       iNewParent = pSubSrc->a[i].iCursor;
@@ -5346,8 +5367,8 @@ static int disableUnusedSubqueryResultColumns(SrcItem *pItem){
   }
   assert( pItem->pSTab!=0 );
   pTab = pItem->pSTab;
-  assert( pItem->sq.pSelect!=0 );
-  pSub = pItem->sq.pSelect;
+  assert( pItem->fg.isSubquery );
+  pSub = pItem->u4.pSubq->pSelect;
   assert( pSub->pEList->nExpr==pTab->nCol );
   for(pX=pSub; pX; pX=pX->pPrior){
     if( (pX->selFlags & (SF_Distinct|SF_Aggregate))!=0 ){
@@ -5476,7 +5497,7 @@ static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){
   if( p->pWhere
    || p->pEList->nExpr!=1
    || p->pSrc->nSrc!=1
-   || p->pSrc->a[0].sq.pSelect
+   || p->pSrc->a[0].fg.isSubquery
    || pAggInfo->nFunc!=1
    || p->pHaving
   ){
@@ -5776,10 +5797,12 @@ static int resolveFromTermToCte(
     pTab->iPKey = -1;
     pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
     pTab->tabFlags |= TF_Ephemeral | TF_NoVisibleRowid;
-    pFrom->sq.pSelect = sqlite3SelectDup(db, pCte->pSelect, 0);
+    sqlite3SrcItemAttachSubquery(pParse, pFrom, pCte->pSelect, 1);
     if( db->mallocFailed ) return 2;
-    assert( pFrom->sq.pSelect );
-    pFrom->sq.pSelect->selFlags |= SF_CopyCte;
+    assert( pFrom->fg.isSubquery && pFrom->u4.pSubq );
+    pSel = pFrom->u4.pSubq->pSelect;
+    assert( pSel!=0 );
+    pSel->selFlags |= SF_CopyCte;
     if( pFrom->fg.isIndexedBy ){
       sqlite3ErrorMsg(pParse, "no such index: \"%s\"", pFrom->u1.zIndexedBy);
       return 2;
@@ -5789,7 +5812,7 @@ static int resolveFromTermToCte(
     pCteUse->nUse++;
 
     /* Check if this is a recursive CTE. */
-    pRecTerm = pSel = pFrom->sq.pSelect;
+    pRecTerm = pSel;
     bMayRecursive = ( pSel->op==TK_ALL || pSel->op==TK_UNION );
     while( bMayRecursive && pRecTerm->op==pSel->op ){
       int i;
@@ -5904,9 +5927,12 @@ void sqlite3SelectPopWith(Walker *pWalker, Select *p){
 ** SQLITE_NOMEM.
 */
 int sqlite3ExpandSubquery(Parse *pParse, SrcItem *pFrom){
-  Select *pSel = pFrom->sq.pSelect;
+  Select *pSel;
   Table *pTab;
 
+  assert( pFrom->fg.isSubquery );
+  assert( pFrom->u4.pSubq!=0 );
+  pSel = pFrom->u4.pSubq->pSelect;
   assert( pSel );
   pFrom->pSTab = pTab = sqlite3DbMallocZero(pParse->db, sizeof(Table));
   if( pTab==0 ) return SQLITE_NOMEM;
@@ -6033,7 +6059,9 @@ static int selectExpander(Walker *pWalker, Select *p){
     assert( pFrom->fg.isRecursive==0 );
     if( pFrom->zName==0 ){
 #ifndef SQLITE_OMIT_SUBQUERY
-      Select *pSel = pFrom->sq.pSelect;
+      Select *pSel;
+      assert( pFrom->fg.isSubquery && pFrom->u4.pSubq!=0 );
+      pSel = pFrom->u4.pSubq->pSelect;
       /* A sub-query in the FROM clause of a SELECT */
       assert( pSel!=0 );
       assert( pFrom->pSTab==0 );
@@ -6066,7 +6094,7 @@ static int selectExpander(Walker *pWalker, Select *p){
         i16 nCol;
         u8 eCodeOrig = pWalker->eCode;
         if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
-        assert( pFrom->sq.pSelect==0 );
+        assert( pFrom->fg.isSubquery==0 );
         if( IsView(pTab) ){
           if( (db->flags & SQLITE_EnableView)==0
            && pTab->pSchema!=db->aDb[1].pSchema
@@ -6074,7 +6102,7 @@ static int selectExpander(Walker *pWalker, Select *p){
             sqlite3ErrorMsg(pParse, "access to view \"%s\" prohibited",
               pTab->zName);
           }
-          pFrom->sq.pSelect = sqlite3SelectDup(db, pTab->u.view.pSelect, 0);
+          sqlite3SrcItemAttachSubquery(pParse, pFrom, pTab->u.view.pSelect, 1);
         }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
         else if( ALWAYS(IsVirtual(pTab))
@@ -6090,7 +6118,9 @@ static int selectExpander(Walker *pWalker, Select *p){
         nCol = pTab->nCol;
         pTab->nCol = -1;
         pWalker->eCode = 1;  /* Turn on Select.selId renumbering */
-        sqlite3WalkSelect(pWalker, pFrom->sq.pSelect);
+        if( pFrom->fg.isSubquery ){
+          sqlite3WalkSelect(pWalker, pFrom->u4.pSubq->pSelect);
+        }
         pWalker->eCode = eCodeOrig;
         pTab->nCol = nCol;
       }
@@ -6188,11 +6218,11 @@ static int selectExpander(Walker *pWalker, Select *p){
             zTabName = pTab->zName;
           }
           if( db->mallocFailed ) break;
-          assert( (int)pFrom->fg.isNestedFrom ==
-                                         IsNestedFrom(pFrom->sq.pSelect) );
+          assert( (int)pFrom->fg.isNestedFrom == IsNestedFrom(pFrom) );
           if( pFrom->fg.isNestedFrom ){
-            assert( pFrom->sq.pSelect!=0 );
-            pNestedFrom = pFrom->sq.pSelect->pEList;
+            assert( pFrom->fg.isSubquery && pFrom->u4.pSubq );
+            assert( pFrom->u4.pSubq->pSelect!=0 );
+            pNestedFrom = pFrom->u4.pSubq->pSelect->pEList;
             assert( pNestedFrom!=0 );
             assert( pNestedFrom->nExpr==pTab->nCol );
             assert( VisibleRowid(pTab)==0 || ViewCanHaveRowid );
@@ -6433,12 +6463,10 @@ static void selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
   for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
     Table *pTab = pFrom->pSTab;
     assert( pTab!=0 );
-    if( (pTab->tabFlags & TF_Ephemeral)!=0 ){
+    if( (pTab->tabFlags & TF_Ephemeral)!=0 && pFrom->fg.isSubquery ){
       /* A sub-query in the FROM clause of a SELECT */
-      Select *pSel = pFrom->sq.pSelect;
-      if( pSel ){
-        sqlite3SubqueryColumnTypes(pParse, pTab, pSel, SQLITE_AFF_NONE);
-      }
+      Select *pSel = pFrom->u4.pSubq->pSelect;
+      sqlite3SubqueryColumnTypes(pParse, pTab, pSel, SQLITE_AFF_NONE);
     }
   }
 }
@@ -7085,25 +7113,28 @@ static SrcItem *isSelfJoinView(
   int iFirst, int iEnd        /* Range of FROM-clause entries to search. */
 ){
   SrcItem *pItem;
-  assert( pThis->sq.pSelect!=0 );
-  if( pThis->sq.pSelect->selFlags & SF_PushDown ) return 0;
+  Select *pSel;
+  assert( pThis->fg.isSubquery );
+  pSel = pThis->u4.pSubq->pSelect;
+  assert( pSel!=0 );
+  if( pSel->selFlags & SF_PushDown ) return 0;
   while( iFirst<iEnd ){
     Select *pS1;
     pItem = &pTabList->a[iFirst++];
-    if( pItem->sq.pSelect==0 ) continue;
+    if( !pItem->fg.isSubquery ) continue;
     if( pItem->fg.viaCoroutine ) continue;
     if( pItem->zName==0 ) continue;
     assert( pItem->pSTab!=0 );
     assert( pThis->pSTab!=0 );
     if( pItem->pSTab->pSchema!=pThis->pSTab->pSchema ) continue;
     if( sqlite3_stricmp(pItem->zName, pThis->zName)!=0 ) continue;
-    pS1 = pItem->sq.pSelect;
-    if( pItem->pSTab->pSchema==0 && pThis->sq.pSelect->selId!=pS1->selId ){
+    pS1 = pItem->u4.pSubq->pSelect;
+    if( pItem->pSTab->pSchema==0 && pSel->selId!=pS1->selId ){
       /* The query flattener left two different CTE tables with identical
       ** names in the same FROM clause. */
       continue;
     }
-    if( pItem->sq.pSelect->selFlags & SF_PushDown ){
+    if( pS1->selFlags & SF_PushDown ){
       /* The view was modified by some other optimization such as
       ** pushDownWhereTerms() */
       continue;
@@ -7147,6 +7178,7 @@ static int countOfViewOptimization(Parse *pParse, Select *p){
   Expr *pExpr;
   Expr *pCount;
   sqlite3 *db;
+  SrcItem *pFrom;
   if( (p->selFlags & SF_Aggregate)==0 ) return 0;   /* This is an aggregate */
   if( p->pEList->nExpr!=1 ) return 0;               /* Single result column */
   if( p->pWhere ) return 0;
@@ -7161,8 +7193,9 @@ static int countOfViewOptimization(Parse *pParse, Select *p){
   if( pExpr->x.pList!=0 ) return 0;                 /* Must be count(*) */
   if( p->pSrc->nSrc!=1 ) return 0;                  /* One table in FROM  */
   if( ExprHasProperty(pExpr, EP_WinFunc) ) return 0;/* Not a window function */
-  pSub = p->pSrc->a[0].sq.pSelect;
-  if( pSub==0 ) return 0;                           /* The FROM is a subquery */
+  pFrom = p->pSrc->a;
+  if( pFrom->fg.isSubquery==0 ) return 0;    /* FROM is a subquery */
+  pSub = pFrom->u4.pSubq->pSelect;
   if( pSub->pPrior==0 ) return 0;                   /* Must be a compound */
   if( pSub->selFlags & SF_CopyCte ) return 0;       /* Not a CTE */
   do{
@@ -7171,7 +7204,7 @@ static int countOfViewOptimization(Parse *pParse, Select *p){
     if( pSub->pLimit ) return 0;                      /* No LIMIT clause */
     if( pSub->selFlags & SF_Aggregate ) return 0;     /* Not an aggregate */
     assert( pSub->pHaving==0 );  /* Due to the previous */
-   pSub = pSub->pPrior;                              /* Repeat over compound */
+    pSub = pSub->pPrior;                              /* Repeat over compound */
   }while( pSub );
 
   /* If we reach this point then it is OK to perform the transformation */
@@ -7179,8 +7212,7 @@ static int countOfViewOptimization(Parse *pParse, Select *p){
   db = pParse->db;
   pCount = pExpr;
   pExpr = 0;
-  pSub = p->pSrc->a[0].sq.pSelect;
-  p->pSrc->a[0].sq.pSelect = 0;
+  pSub = sqlite3SubqueryDetach(db, pFrom);
   sqlite3SrcListDelete(db, p->pSrc);
   p->pSrc = sqlite3DbMallocZero(pParse->db, sizeof(*p->pSrc));
   while( pSub ){
@@ -7228,9 +7260,9 @@ static int sameSrcAlias(SrcItem *p0, SrcList *pSrc){
     if( p0->pSTab==p1->pSTab && 0==sqlite3_stricmp(p0->zAlias, p1->zAlias) ){
       return 1;
     }
-    if( p1->sq.pSelect
-     && (p1->sq.pSelect->selFlags & SF_NestedFrom)!=0
-     && sameSrcAlias(p0, p1->sq.pSelect->pSrc)
+    if( p1->fg.isSubquery
+     && (p1->u4.pSubq->pSelect->selFlags & SF_NestedFrom)!=0
+     && sameSrcAlias(p0, p1->u4.pSubq->pSelect->pSrc)
     ){
       return 1;
     }
@@ -7295,7 +7327,7 @@ static int fromClauseTermCanBeCoroutine(
     if( i==0 ) break;
     i--;
     pItem--;
-    if( pItem->sq.pSelect!=0 ) return 0;                          /* (1c-i) */
+    if( pItem->fg.isSubquery ) return 0;                          /* (1c-i) */
   }
   return 1;
 }
@@ -7445,7 +7477,7 @@ int sqlite3Select(
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
   for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
     SrcItem *pItem = &pTabList->a[i];
-    Select *pSub = pItem->sq.pSelect;
+    Select *pSub = pItem->fg.isSubquery ? pItem->u4.pSubq->pSelect : 0;
     Table *pTab = pItem->pSTab;
 
     /* The expander should have already created transient Table objects
@@ -7664,6 +7696,7 @@ int sqlite3Select(
     SrcItem *pItem = &pTabList->a[i];
     SrcItem *pPrior;
     SelectDest dest;
+    Subquery *pSubq;
     Select *pSub;
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
     const char *zSavedAuthContext;
@@ -7699,11 +7732,14 @@ int sqlite3Select(
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
     /* Generate code for all sub-queries in the FROM clause
     */
-    pSub = pItem->sq.pSelect;
-    if( pSub==0 || pItem->sq.addrFillSub!=0 ) continue;
+    if( pItem->fg.isSubquery==0 ) continue;
+    pSubq = pItem->u4.pSubq;
+    assert( pSubq!=0 );
+    pSub = pSubq->pSelect;
+    if( pSubq->addrFillSub!=0 ) continue;
 
     /* The code for a subquery should only be generated once. */
-    assert( pItem->sq.addrFillSub==0 );
+    assert( pSubq->addrFillSub==0 );
 
     /* Increment Parse.nHeight by the height of the largest expression
     ** tree referred to by this, the parent select. The child select
@@ -7729,8 +7765,7 @@ int sqlite3Select(
         sqlite3TreeViewSelect(0, p, 0);
       }
 #endif
-      assert( pItem->sq.pSelect 
-           && (pItem->sq.pSelect->selFlags & SF_PushDown)!=0 );
+      assert( pSubq->pSelect && (pSub->selFlags & SF_PushDown)!=0 );
     }else{
       TREETRACE(0x4000,pParse,p,("WHERE-lcause push-down not possible\n"));
     }
@@ -7762,17 +7797,17 @@ int sqlite3Select(
       */
       int addrTop = sqlite3VdbeCurrentAddr(v)+1;
     
-      pItem->sq.regReturn = ++pParse->nMem;
-      sqlite3VdbeAddOp3(v, OP_InitCoroutine, pItem->sq.regReturn, 0, addrTop);
+      pSubq->regReturn = ++pParse->nMem;
+      sqlite3VdbeAddOp3(v, OP_InitCoroutine, pSubq->regReturn, 0, addrTop);
       VdbeComment((v, "%!S", pItem));
-      pItem->sq.addrFillSub = addrTop;
-      sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->sq.regReturn);
+      pSubq->addrFillSub = addrTop;
+      sqlite3SelectDestInit(&dest, SRT_Coroutine, pSubq->regReturn);
       ExplainQueryPlan((pParse, 1, "CO-ROUTINE %!S", pItem));
       sqlite3Select(pParse, pSub, &dest);
       pItem->pSTab->nRowLogEst = pSub->nSelectRow;
       pItem->fg.viaCoroutine = 1;
-      pItem->sq.regResult = dest.iSdst;
-      sqlite3VdbeEndCoroutine(v, pItem->sq.regReturn);
+      pSubq->regResult = dest.iSdst;
+      sqlite3VdbeEndCoroutine(v, pSubq->regReturn);
       sqlite3VdbeJumpHere(v, addrTop-1);
       sqlite3ClearTempRegCache(pParse);
     }else if( pItem->fg.isCte && pItem->u2.pCteUse->addrM9e>0 ){
@@ -7790,12 +7825,16 @@ int sqlite3Select(
     }else if( (pPrior = isSelfJoinView(pTabList, pItem, 0, i))!=0 ){
       /* This view has already been materialized by a prior entry in
       ** this same FROM clause.  Reuse it. */
-      if( pPrior->sq.addrFillSub ){
-        sqlite3VdbeAddOp2(v, OP_Gosub, pPrior->sq.regReturn,
-                                       pPrior->sq.addrFillSub);
+      Subquery *pPriorSubq;
+      assert( pPrior->fg.isSubquery );
+      pPriorSubq = pPrior->u4.pSubq;
+      assert( pPriorSubq!=0 );
+      if( pPriorSubq->addrFillSub ){
+        sqlite3VdbeAddOp2(v, OP_Gosub, pPriorSubq->regReturn,
+                                       pPriorSubq->addrFillSub);
       }
       sqlite3VdbeAddOp2(v, OP_OpenDup, pItem->iCursor, pPrior->iCursor);
-      pSub->nSelectRow = pPrior->sq.pSelect->nSelectRow;
+      pSub->nSelectRow = pPriorSubq->pSelect->nSelectRow;
     }else{
       /* Materialize the view.  If the view is not correlated, generate a
       ** subroutine to do the materialization so that subsequent uses of
@@ -7806,9 +7845,9 @@ int sqlite3Select(
       int addrExplain;
 #endif
 
-      pItem->sq.regReturn = ++pParse->nMem;
+      pSubq->regReturn = ++pParse->nMem;
       topAddr = sqlite3VdbeAddOp0(v, OP_Goto);
-      pItem->sq.addrFillSub = topAddr+1;
+      pSubq->addrFillSub = topAddr+1;
       pItem->fg.isMaterialized = 1;
       if( pItem->fg.isCorrelated==0 ){
         /* If the subquery is not correlated and if we are not inside of
@@ -7825,15 +7864,15 @@ int sqlite3Select(
       sqlite3Select(pParse, pSub, &dest);
       pItem->pSTab->nRowLogEst = pSub->nSelectRow;
       if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
-      sqlite3VdbeAddOp2(v, OP_Return, pItem->sq.regReturn, topAddr+1);
+      sqlite3VdbeAddOp2(v, OP_Return, pSubq->regReturn, topAddr+1);
       VdbeComment((v, "end %!S", pItem));
       sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1);
       sqlite3VdbeJumpHere(v, topAddr);
       sqlite3ClearTempRegCache(pParse);
       if( pItem->fg.isCte && pItem->fg.isCorrelated==0 ){
         CteUse *pCteUse = pItem->u2.pCteUse;
-        pCteUse->addrM9e = pItem->sq.addrFillSub;
-        pCteUse->regRtn = pItem->sq.regReturn;
+        pCteUse->addrM9e = pSubq->addrFillSub;
+        pCteUse->regRtn = pSubq->regReturn;
         pCteUse->iCur = pItem->iCursor;
         pCteUse->nRowEst = pSub->nSelectRow;
       }
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 54e4f2db73..c282023de4 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1335,6 +1335,7 @@ typedef struct Savepoint Savepoint;
 typedef struct Select Select;
 typedef struct SQLiteThread SQLiteThread;
 typedef struct SelectDest SelectDest;
+typedef struct Subquery Subquery;
 typedef struct SrcItem SrcItem;
 typedef struct SrcList SrcList;
 typedef struct sqlite3_str StrAccum; /* Internal alias for sqlite3_str */
@@ -3275,6 +3276,16 @@ struct IdList {
 #define EU4_IDX    1   /* Uses IdList.a.u4.idx */
 #define EU4_EXPR   2   /* Uses IdList.a.u4.pExpr -- NOT CURRENTLY USED */
 
+/*
+** Details of the implementation of a subquery.
+*/
+struct Subquery {
+  Select *pSelect;  /* A SELECT statement used in place of a table name */
+  int addrFillSub;  /* Address of subroutine to initialize a subquery */
+  int regReturn;    /* Register holding return address of addrFillSub */
+  int regResult;    /* Registers holding results of a co-routine */
+};
+
 /*
 ** The SrcItem object represents a single term in the FROM clause of a query.
 ** The SrcList object is mostly an array of SrcItems.
@@ -3287,10 +3298,15 @@ struct IdList {
 ** In the colUsed field, the high-order bit (bit 63) is set if the table
 ** contains more than 63 columns and the 64-th or later column is used.
 **
+** Intenstive use of "union" helps keep the size of the object small.  This
+** has been shown to boost performance due to less time spend initializing
+** fields to zero when a new instance of this object is allocated.  The unions
+** also help SrcItem, and hence SrcList and Select, use less memory.
+**
 ** Union member validity:
 **
-**    u1.zIndexedBy      fg.isIndexedBy && !fg.isTabFunc
-**    u1.pFuncArg        fg.isTabFunc   && !fg.isIndexedBy
+**    u1.zIndexedBy      fg.isIndexedBy
+**    u1.pFuncArg        fg.isTabFunc
 **    u1.nRow            !fg.isTabFunc  && !fg.isIndexedBy
 **
 **    u2.pIBIndex        fg.isIndexedBy && !fg.isCte
@@ -3299,23 +3315,19 @@ struct IdList {
 **    u3.pOn             fg.isUsing==0
 **    u3.pUsing          fg.isUsing==1
 **
-**    u4.zDatabase       fg.fixedSchema==0
+**    u4.zDatabase       fg.fixedSchema==0 && !fg.isSubquery
 **    u4.pSchema         fg.fixedSchema==1
+**    u4.pSubq           fg.isSubquery
 */
 struct SrcItem {
   char *zName;      /* Name of the table */
   char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
   Table *pSTab;     /* Table object for zName. Mnemonic: Srcitem-TABle */
-  struct SrcItemSubquery {
-    Select *pSelect;  /* A SELECT statement used in place of a table name */
-    int addrFillSub;  /* Address of subroutine to initialize a subquery */
-    int regReturn;    /* Register holding return address of addrFillSub */
-    int regResult;    /* Registers holding results of a co-routine */
-  } sq;
   struct {
     u8 jointype;      /* Type of join between this table and the previous */
     unsigned notIndexed :1;    /* True if there is a NOT INDEXED clause */
     unsigned isIndexedBy :1;   /* True if there is an INDEXED BY clause */
+    unsigned isSubquery :1;    /* True if this term is a subquery */
     unsigned isTabFunc :1;     /* True if table-valued-function syntax */
     unsigned isCorrelated :1;  /* True if sub-query is correlated */
     unsigned isMaterialized:1; /* This is a materialized view */
@@ -3350,6 +3362,7 @@ struct SrcItem {
   union {
     Schema *pSchema;  /* Schema to which this item is fixed */
     char *zDatabase;  /* Name of database holding this table */
+    Subquery *pSubq;  /* Description of a subquery */
   } u4;
 };
 
@@ -3610,8 +3623,10 @@ struct Select {
 #define SF_UpdateFrom   0x10000000 /* Query originates with UPDATE FROM */
 #define SF_Correlated   0x20000000 /* True if references the outer context */
 
-/* True if S exists and has SF_NestedFrom */
-#define IsNestedFrom(S) ((S)!=0 && ((S)->selFlags&SF_NestedFrom)!=0)
+/* True if SrcList item X is a subquery that has SF_NestedFrom */
+#define IsNestedFrom(X) \
+   ((X)->fg.isSubquery && \
+    ((X)->u4.pSubq->pSelect->selFlags&SF_NestedFrom)!=0)
 
 /*
 ** The results of a SELECT can be distributed in several ways, as defined
@@ -5003,6 +5018,9 @@ int sqlite3IdListIndex(IdList*,const char*);
 SrcList *sqlite3SrcListEnlarge(Parse*, SrcList*, int, int);
 SrcList *sqlite3SrcListAppendList(Parse *pParse, SrcList *p1, SrcList *p2);
 SrcList *sqlite3SrcListAppend(Parse*, SrcList*, Token*, Token*);
+void sqlite3SubqueryDelete(sqlite3*,Subquery*);
+Select *sqlite3SubqueryDetach(sqlite3*,SrcItem*);
+int sqlite3SrcItemAttachSubquery(Parse*, SrcItem*, Select*, int);
 SrcList *sqlite3SrcListAppendFromTerm(Parse*, SrcList*, Token*, Token*,
                                       Token*, Select*, OnOrUsing*);
 void sqlite3SrcListIndexedBy(Parse *, SrcList *, Token *);
diff --git a/src/treeview.c b/src/treeview.c
index 0c9fdc5266..dbd54b3466 100644
--- a/src/treeview.c
+++ b/src/treeview.c
@@ -230,19 +230,19 @@ void sqlite3TreeViewSrcList(TreeView *pView, const SrcList *pSrc){
     sqlite3StrAccumFinish(&x);
     sqlite3TreeViewItem(pView, zLine, i<pSrc->nSrc-1);
     n = 0;
-    if( pItem->sq.pSelect ) n++;
+    if( pItem->fg.isSubquery ) n++;
     if( pItem->fg.isTabFunc ) n++;
     if( pItem->fg.isUsing ) n++;
     if( pItem->fg.isUsing ){
       sqlite3TreeViewIdList(pView, pItem->u3.pUsing, (--n)>0, "USING");
     }
-    if( pItem->sq.pSelect ){
+    if( pItem->fg.isSubquery ){
       if( pItem->pSTab ){
         Table *pTab = pItem->pSTab;
         sqlite3TreeViewColumnList(pView, pTab->aCol, pTab->nCol, 1);
       }
-      assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->sq.pSelect) );
-      sqlite3TreeViewSelect(pView, pItem->sq.pSelect, (--n)>0);
+      assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem) );
+      sqlite3TreeViewSelect(pView, pItem->u4.pSubq->pSelect, (--n)>0);
     }
     if( pItem->fg.isTabFunc ){
       sqlite3TreeViewExprList(pView, pItem->u1.pFuncArg, 0, "func-args:");
diff --git a/src/walker.c b/src/walker.c
index 27963c2234..c8735e39b8 100644
--- a/src/walker.c
+++ b/src/walker.c
@@ -171,7 +171,9 @@ int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
   pSrc = p->pSrc;
   if( ALWAYS(pSrc) ){
     for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
-      if( pItem->sq.pSelect && sqlite3WalkSelect(pWalker, pItem->sq.pSelect) ){
+      if( pItem->fg.isSubquery
+       && sqlite3WalkSelect(pWalker, pItem->u4.pSubq->pSelect)
+      ){
         return WRC_Abort;
       }
       if( pItem->fg.isTabFunc
diff --git a/src/where.c b/src/where.c
index ded5f06816..c9f6b97c94 100644
--- a/src/where.c
+++ b/src/where.c
@@ -1161,9 +1161,14 @@ static SQLITE_NOINLINE void constructAutomaticIndex(
   /* Fill the automatic index with content */
   assert( pSrc == &pWC->pWInfo->pTabList->a[pLevel->iFrom] );
   if( pSrc->fg.viaCoroutine ){
-    int regYield = pSrc->sq.regReturn;
+    int regYield;
+    Subquery *pSubq;
+    assert( pSrc->fg.isSubquery );
+    pSubq = pSrc->u4.pSubq;
+    assert( pSubq!=0 );
+    regYield = pSubq->regReturn;
     addrCounter = sqlite3VdbeAddOp2(v, OP_Integer, 0, 0);
-    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pSrc->sq.addrFillSub);
+    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pSubq->addrFillSub);
     addrTop =  sqlite3VdbeAddOp1(v, OP_Yield, regYield);
     VdbeCoverage(v);
     VdbeComment((v, "next row of %s", pSrc->pSTab->zName));
@@ -1188,11 +1193,12 @@ static SQLITE_NOINLINE void constructAutomaticIndex(
   sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
   if( pPartial ) sqlite3VdbeResolveLabel(v, iContinue);
   if( pSrc->fg.viaCoroutine ){
+    assert( pSrc->fg.isSubquery && pSrc->u4.pSubq!=0 );
     sqlite3VdbeChangeP2(v, addrCounter, regBase+n);
     testcase( pParse->db->mallocFailed );
     assert( pLevel->iIdxCur>0 );
     translateColumnToCopy(pParse, addrTop, pLevel->iTabCur,
-                          pSrc->sq.regResult, pLevel->iIdxCur);
+                          pSrc->u4.pSubq->regResult, pLevel->iIdxCur);
     sqlite3VdbeGoto(v, addrTop);
     pSrc->fg.viaCoroutine = 0;
   }else{
@@ -4010,9 +4016,9 @@ static int whereLoopAddBtree(
 #endif
       ApplyCostMultiplier(pNew->rRun, pTab->costMult);
       whereLoopOutputAdjust(pWC, pNew, rSize);
-      if( pSrc->sq.pSelect ){
+      if( pSrc->fg.isSubquery ){
         if( pSrc->fg.viaCoroutine ) pNew->wsFlags |= WHERE_COROUTINE;
-        pNew->u.btree.pOrderBy = pSrc->sq.pSelect->pOrderBy;
+        pNew->u.btree.pOrderBy = pSrc->u4.pSubq->pSelect->pOrderBy;
       }
       rc = whereLoopInsert(pBuilder, pNew);
       pNew->nOut = rSize;
@@ -6421,8 +6427,8 @@ static SQLITE_NOINLINE void whereReverseScanOrder(WhereInfo *pWInfo){
     SrcItem *pItem = &pWInfo->pTabList->a[ii];
     if( !pItem->fg.isCte
      || pItem->u2.pCteUse->eM10d!=M10d_Yes
-     || NEVER(pItem->sq.pSelect==0)
-     || pItem->sq.pSelect->pOrderBy==0
+     || NEVER(pItem->fg.isSubquery==0)
+     || pItem->u4.pSubq->pSelect->pOrderBy==0
     ){
       pWInfo->revMask |= MASKBIT(ii);
     }
@@ -7115,11 +7121,14 @@ WhereInfo *sqlite3WhereBegin(
     wsFlags = pLevel->pWLoop->wsFlags;
     pSrc = &pTabList->a[pLevel->iFrom];
     if( pSrc->fg.isMaterialized ){
+      Subquery *pSubq;
+      assert( pSrc->fg.isSubquery );
+      pSubq = pSrc->u4.pSubq;
       if( pSrc->fg.isCorrelated ){
-        sqlite3VdbeAddOp2(v, OP_Gosub, pSrc->sq.regReturn,pSrc->sq.addrFillSub);
+        sqlite3VdbeAddOp2(v, OP_Gosub, pSubq->regReturn, pSubq->addrFillSub);
       }else{
         int iOnce = sqlite3VdbeAddOp0(v, OP_Once);  VdbeCoverage(v);
-        sqlite3VdbeAddOp2(v, OP_Gosub, pSrc->sq.regReturn,pSrc->sq.addrFillSub);
+        sqlite3VdbeAddOp2(v, OP_Gosub, pSubq->regReturn, pSubq->addrFillSub);
         sqlite3VdbeJumpHere(v, iOnce);
       }
     }
@@ -7334,7 +7343,8 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
         assert( pLevel->iTabCur==pSrc->iCursor );
         if( pSrc->fg.viaCoroutine ){
           int m, n;
-          n = pSrc->sq.regResult;
+          assert( pSrc->fg.isSubquery );
+          n = pSrc->u4.pSubq->regResult;
           assert( pSrc->pSTab!=0 );
           m = pSrc->pSTab->nCol;
           sqlite3VdbeAddOp3(v, OP_Null, 0, n, n+m-1);
@@ -7388,9 +7398,10 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
     */
     if( pTabItem->fg.viaCoroutine ){
       testcase( pParse->db->mallocFailed );
-      assert( pTabItem->sq.regResult>=0 );
+      assert( pTabItem->fg.isSubquery );
+      assert( pTabItem->u4.pSubq->regResult>=0 );
       translateColumnToCopy(pParse, pLevel->addrBody, pLevel->iTabCur,
-                            pTabItem->sq.regResult, 0);
+                            pTabItem->u4.pSubq->regResult, 0);
       continue;
     }
 
diff --git a/src/wherecode.c b/src/wherecode.c
index ebc71d1102..b0c0d9aedd 100644
--- a/src/wherecode.c
+++ b/src/wherecode.c
@@ -317,7 +317,9 @@ void sqlite3WhereAddScanStatus(
         sqlite3VdbeScanStatusRange(v, addrExplain, -1, pLvl->iIdxCur);
       }
     }else{
-      int addr = pSrclist->a[pLvl->iFrom].sq.addrFillSub;
+      int addr;
+      assert( pSrclist->a[pLvl->iFrom].fg.isSubquery );
+      addr = pSrclist->a[pLvl->iFrom].u4.pSubq->addrFillSub;
       VdbeOp *pOp = sqlite3VdbeGetOp(v, addr-1);
       assert( sqlite3VdbeDb(v)->mallocFailed || pOp->opcode==OP_InitCoroutine );
       assert( sqlite3VdbeDb(v)->mallocFailed || pOp->p2>addr );
@@ -1510,8 +1512,12 @@ Bitmask sqlite3WhereCodeOneLoopStart(
 
   /* Special case of a FROM clause subquery implemented as a co-routine */
   if( pTabItem->fg.viaCoroutine ){
-    int regYield = pTabItem->sq.regReturn;
-    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield,0,pTabItem->sq.addrFillSub);
+    int regYield;
+    Subquery *pSubq;
+    assert( pTabItem->fg.isSubquery && pTabItem->u4.pSubq!=0 );
+    pSubq = pTabItem->u4.pSubq;
+    regYield = pSubq->regReturn;
+    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pSubq->addrFillSub);
     pLevel->p2 =  sqlite3VdbeAddOp2(v, OP_Yield, regYield, addrBrk);
     VdbeCoverage(v);
     VdbeComment((v, "next row of %s", pTabItem->pSTab->zName));
@@ -2819,9 +2825,13 @@ SQLITE_NOINLINE void sqlite3WhereRightJoinLoop(
     pRight = &pWInfo->pTabList->a[pWInfo->a[k].iFrom];
     mAll |= pWInfo->a[k].pWLoop->maskSelf;
     if( pRight->fg.viaCoroutine ){
+      Subquery *pSubq;
+      assert( pRight->fg.isSubquery && pRight->u4.pSubq!=0 );
+      pSubq = pRight->u4.pSubq;
+      assert( pSubq->pSelect!=0 && pSubq->pSelect->pEList!=0 );
       sqlite3VdbeAddOp3(
-          v, OP_Null, 0, pRight->sq.regResult, 
-          pRight->sq.regResult + pRight->sq.pSelect->pEList->nExpr-1
+          v, OP_Null, 0, pSubq->regResult, 
+          pSubq->regResult + pSubq->pSelect->pEList->nExpr-1
       );
     }
     sqlite3VdbeAddOp1(v, OP_NullRow, pWInfo->a[k].iTabCur);
diff --git a/src/whereexpr.c b/src/whereexpr.c
index 766754828d..ae26e85d25 100644
--- a/src/whereexpr.c
+++ b/src/whereexpr.c
@@ -958,7 +958,9 @@ static Bitmask exprSelectUsage(WhereMaskSet *pMaskSet, Select *pS){
     if( ALWAYS(pSrc!=0) ){
       int i;
       for(i=0; i<pSrc->nSrc; i++){
-        mask |= exprSelectUsage(pMaskSet, pSrc->a[i].sq.pSelect);
+        if( pSrc->a[i].fg.isSubquery ){
+          mask |= exprSelectUsage(pMaskSet, pSrc->a[i].u4.pSubq->pSelect);
+        }
         if( pSrc->a[i].fg.isUsing==0 ){
           mask |= sqlite3WhereExprUsage(pMaskSet, pSrc->a[i].u3.pOn);
         }
diff --git a/src/window.c b/src/window.c
index 9829d1740b..d4083beeb3 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1077,9 +1077,10 @@ int sqlite3WindowRewrite(Parse *pParse, Select *p){
     assert( pSub!=0 || p->pSrc==0 ); /* Due to db->mallocFailed test inside
                                      ** of sqlite3DbMallocRawNN() called from
                                      ** sqlite3SrcListAppend() */
-    if( p->pSrc ){
+    if( p->pSrc==0 ){
+      sqlite3SelectDelete(db, pSub);
+    }else if( sqlite3SrcItemAttachSubquery(pParse, &p->pSrc->a[0], pSub, 0) ){
       Table *pTab2;
-      p->pSrc->a[0].sq.pSelect = pSub;
       p->pSrc->a[0].fg.isCorrelated = 1;
       sqlite3SrcListAssignCursors(pParse, p->pSrc);
       pSub->selFlags |= SF_Expanded|SF_OrderByReqd;
@@ -1101,8 +1102,6 @@ int sqlite3WindowRewrite(Parse *pParse, Select *p){
         w.xSelectCallback2 = sqlite3WalkerDepthDecrease;
         sqlite3WalkSelect(&w, pSub);
       }
-    }else{
-      sqlite3SelectDelete(db, pSub);
     }
     if( db->mallocFailed ) rc = SQLITE_NOMEM;
 
@@ -1389,10 +1388,15 @@ int sqlite3WindowCompare(
 ** and initialize registers and cursors used by sqlite3WindowCodeStep().
 */
 void sqlite3WindowCodeInit(Parse *pParse, Select *pSelect){
-  int nEphExpr = pSelect->pSrc->a[0].sq.pSelect->pEList->nExpr;
-  Window *pMWin = pSelect->pWin;
   Window *pWin;
-  Vdbe *v = sqlite3GetVdbe(pParse);
+  int nEphExpr;
+  Window *pMWin;
+  Vdbe *v;
+
+  assert( pSelect->pSrc->a[0].fg.isSubquery );
+  nEphExpr = pSelect->pSrc->a[0].u4.pSubq->pSelect->pEList->nExpr;
+  pMWin = pSelect->pWin;
+  v = sqlite3GetVdbe(pParse);
 
   sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pMWin->iEphCsr, nEphExpr);
   sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+1, pMWin->iEphCsr);

From ff4ad29d05156598d70b8328cbfb352114446bc3 Mon Sep 17 00:00:00 2001
From: drh <>
Date: Tue, 20 Aug 2024 16:50:21 +0000
Subject: [PATCH 04/10] Memory issues fixes so that mdevtest now passes.

FossilOrigin-Name: b249516f6a6650808e035ec219e762bf24dcb7c32a6235984b995d08d07d35d8
---
 manifest      | 14 +++++++-------
 manifest.uuid |  2 +-
 src/build.c   |  6 ++++--
 src/insert.c  |  8 +++++---
 4 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/manifest b/manifest
index 30b1edeab1..06a26110e0 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Refactor\sthe\sSrcItem\sobject\sso\sthat\sinformation\sabout\ssubqueries\sis\sstored\nin\sa\sseparately\sallocated\sSubquery\sobject.\s\sThis\sreduces\sthe\smemory\srequirements\nfor\sSrcItem\sand\smakes\sthe\scode\srun\sfaster.\s\sIt\salso\sprovides\san\sexpansion\spath\nfor\ssubquery\sprocessing\sthat\sdoes\snot\sburden\ssimple\squeries.\s\sThe\scurrent\nchecking\smostly\sworks,\sbut\sthere\sare\sstill\sissues\sthat\sneed\sto\sbe\stracked\ndown\sand\sfixed.
-D 2024-08-19T22:48:30.539
+C Memory\sissues\sfixes\sso\sthat\smdevtest\snow\spasses.
+D 2024-08-20T16:50:21.429
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -702,7 +702,7 @@ F src/btmutex.c 79a43670447eacc651519a429f6ece9fd638563cf95b469d6891185ddae2b522
 F src/btree.c 8b42fc7d9efdb2df05c30e8f91ff6cfbd979724ae24bf90269028468b7a13333
 F src/btree.h 55066f513eb095db935169dab1dc2f7c7a747ef223c533f5d4ad4dfed346cbd0
 F src/btreeInt.h 98aadb6dcb77b012cab2574d6a728fad56b337fc946839b9898c4b4c969e30b6
-F src/build.c d243a17292e027c1d662e992fbd395123aacc4b74a4a9419d0b010088ba318dd
+F src/build.c 29ebc26d90a9d6e860a3018a6d61fb667c80ec8e80e3798c4164d2349ba28650
 F src/callback.c db3a45e376deff6a16c0058163fe0ae2b73a2945f3f408ca32cf74960b28d490
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 64e4b1227b4ed123146f0aa2989131d1fbd9b927b11e80c9d58c6a68f9cd5ce3
@@ -719,7 +719,7 @@ F src/hash.c 9ee4269fb1d6632a6fecfb9479c93a1f29271bddbbaf215dd60420bcb80c7220
 F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
 F src/hwtime.h f9c2dfb84dce7acf95ce6d289e46f5f9d3d1afd328e53da8f8e9008e3b3caae6
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
-F src/insert.c b07865339e67869ff12d2eee3a1417f4779c742e2a51ae3d14ad45e5168f6f41
+F src/insert.c 37c0c12c6eea72c4dad77699b963be370ca6cbd7d18270ff04f5fe9d6031622d
 F src/json.c 5b6a1d6015997b9ee848a32948720bdb26a0ef2de5a2127ebf7355ce66dbdc0d
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 7432c944ff197046d67a1207790a1b13eec4548c85a9457eb0896bb3641dfb36
@@ -2205,8 +2205,8 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 9f5aeef3cbc2c95267c8f7bf60d5c66971a76789669fb0e8f853273ff6f616f2
-R 0dac77664f5c62d0dcc882ea3148d6f4
+P 8ff5dda8448d7e1a533d7f27db2573ce68fa9956b9d9847ced45e83c1f06bab0
+R c585d13f1a80cb4428e40ac20e746454
 U drh
-Z a11cd0d49c593b1144d9510fd31aa2a7
+Z ce4831b3d2660999f30841c855773e8f
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index ca5d536722..90e67e8d3a 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-8ff5dda8448d7e1a533d7f27db2573ce68fa9956b9d9847ced45e83c1f06bab0
+b249516f6a6650808e035ec219e762bf24dcb7c32a6235984b995d08d07d35d8
diff --git a/src/build.c b/src/build.c
index b585c19719..9cbedf1ec4 100644
--- a/src/build.c
+++ b/src/build.c
@@ -5005,11 +5005,13 @@ int sqlite3SrcItemAttachSubquery(
   Subquery *p;
   if( pSelect==0 ) return SQLITE_OK;
   assert( pItem->fg.isSubquery==0 );
-  if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+  if( pItem->fg.fixedSchema ){
+    pItem->u4.pSchema = 0;
+    pItem->fg.fixedSchema = 0;
+  }else if( pItem->u4.zDatabase!=0 ){
     sqlite3DbFree(pParse->db, pItem->u4.zDatabase);
     pItem->u4.zDatabase = 0;
   }
-  pItem->fg.fixedSchema = 0;
   if( dupSelect ){
     pSelect = sqlite3SelectDup(pParse->db, pSelect, 0);
     if( pSelect==0 ) return 0;
diff --git a/src/insert.c b/src/insert.c
index d65ead2a0b..8214cd9c5c 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -585,9 +585,11 @@ void sqlite3AutoincrementEnd(Parse *pParse){
 void sqlite3MultiValuesEnd(Parse *pParse, Select *pVal){
   if( ALWAYS(pVal) && pVal->pSrc->nSrc>0 ){
     SrcItem *pItem = &pVal->pSrc->a[0];
-    assert( pItem->fg.isSubquery && pItem->u4.pSubq!=0 );
-    sqlite3VdbeEndCoroutine(pParse->pVdbe, pItem->u4.pSubq->regReturn);
-    sqlite3VdbeJumpHere(pParse->pVdbe, pItem->u4.pSubq->addrFillSub - 1);
+    assert( (pItem->fg.isSubquery && pItem->u4.pSubq!=0) || pParse->nErr );
+    if( pItem->fg.isSubquery ){
+      sqlite3VdbeEndCoroutine(pParse->pVdbe, pItem->u4.pSubq->regReturn);
+      sqlite3VdbeJumpHere(pParse->pVdbe, pItem->u4.pSubq->addrFillSub - 1);
+    }
   }
 }
 

From 27c680cc69f181a548d942168e45e37b498684a5 Mon Sep 17 00:00:00 2001
From: drh <>
Date: Tue, 20 Aug 2024 17:24:42 +0000
Subject: [PATCH 05/10] Fix a memory leak so that now all dev tests (including
 TH3) are passing.

FossilOrigin-Name: 3995c45fff0e4bd10bcf49cc16eb1050216426723c63ba56d3ae5ba738c34019
---
 manifest      | 12 ++++++------
 manifest.uuid |  2 +-
 src/select.c  |  7 ++++++-
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/manifest b/manifest
index 06a26110e0..a976440679 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Memory\sissues\sfixes\sso\sthat\smdevtest\snow\spasses.
-D 2024-08-20T16:50:21.429
+C Fix\sa\smemory\sleak\sso\sthat\snow\sall\sdev\stests\s(including\sTH3)\sare\spassing.
+D 2024-08-20T17:24:42.323
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -760,7 +760,7 @@ F src/printf.c 17054fb94ffcf7a28362e9a5af4a0f813bd0c52200ae408eeebddc81feed9274
 F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
 F src/resolve.c 9afed5fd7b9111633bdb74a73cdc47324e28e4dc6c27113e3e9aee38fb9422ab
 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97
-F src/select.c 3e284895745f57de3b37b17fce9eb0e26bc54fccc94ea1ff5342be4360e3674b
+F src/select.c 9aa44e562f2fbfa33e600e3f935369dd9a07e4beb89b344dfc7187dc2adc19ce
 F src/shell.c.in 94571558b0fb28c37a5cf6dbd6ea27285341023a28a8cb5795cd2768fab67704
 F src/sqlite.h.in 1ad9110150773c38ebababbad11b5cb361bcd3997676dec1c91ac5e0416a7b86
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -2205,8 +2205,8 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 8ff5dda8448d7e1a533d7f27db2573ce68fa9956b9d9847ced45e83c1f06bab0
-R c585d13f1a80cb4428e40ac20e746454
+P b249516f6a6650808e035ec219e762bf24dcb7c32a6235984b995d08d07d35d8
+R 5330111931e3ecff89186b5f2d6b0982
 U drh
-Z ce4831b3d2660999f30841c855773e8f
+Z d58fa1c081ceed524dfd09ccfa304c4e
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 90e67e8d3a..0ffd5cf0fb 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-b249516f6a6650808e035ec219e762bf24dcb7c32a6235984b995d08d07d35d8
+3995c45fff0e4bd10bcf49cc16eb1050216426723c63ba56d3ae5ba738c34019
diff --git a/src/select.c b/src/select.c
index 8bddc03bb4..0c10550fac 100644
--- a/src/select.c
+++ b/src/select.c
@@ -5600,12 +5600,17 @@ static int convertCompoundSelectToSubquery(Walker *pWalker, Select *p){
   /* If we reach this point, that means the transformation is required. */
 
   pParse = pWalker->pParse;
+  if( pParse->nErr ) return WRC_Abort;
   db = pParse->db;
   pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
   if( pNew==0 ) return WRC_Abort;
   memset(&dummy, 0, sizeof(dummy));
   pNewSrc = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&dummy,pNew,0);
-  if( pNewSrc==0 ) return WRC_Abort;
+  assert( pNewSrc!=0 || pParse->nErr );
+  if( pParse->nErr ){
+    sqlite3SrcListDelete(db, pNewSrc);
+    return WRC_Abort;
+  }
   *pNew = *p;
   p->pSrc = pNewSrc;
   p->pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ASTERISK, 0));

From ff176231da8496e9fec72fe147eb60316f9c7f60 Mon Sep 17 00:00:00 2001
From: drh <>
Date: Tue, 20 Aug 2024 17:41:44 +0000
Subject: [PATCH 06/10] Fix some stray SrcItem field name fixes.

FossilOrigin-Name: bc5f5ce59e1e4323422bda7d002310923f927a03b4fd42749bf04f6c9853956b
---
 manifest      | 12 ++++++------
 manifest.uuid |  2 +-
 src/delete.c  |  8 ++++----
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/manifest b/manifest
index a976440679..614e098984 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sa\smemory\sleak\sso\sthat\snow\sall\sdev\stests\s(including\sTH3)\sare\spassing.
-D 2024-08-20T17:24:42.323
+C Fix\ssome\sstray\sSrcItem\sfield\sname\sfixes.
+D 2024-08-20T17:41:44.355
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -709,7 +709,7 @@ F src/ctime.c 64e4b1227b4ed123146f0aa2989131d1fbd9b927b11e80c9d58c6a68f9cd5ce3
 F src/date.c 13dd752847afb32ed70510ad7345a5b9c841f51ad904dba5d010f1fa3a6a324e
 F src/dbpage.c 80e46e1df623ec40486da7a5086cb723b0275a6e2a7b01d9f9b5da0f04ba2782
 F src/dbstat.c 3b677254d512fcafd4d0b341bf267b38b235ccfddbef24f9154e19360fa22e43
-F src/delete.c 8aaf9d05d6ff6349a7a6001cbf90c7a46b19b9f52ef2e47aa0415a529d5307a1
+F src/delete.c 3638367ea4ed5d422ee1728a74f0b7a2973af9d7eef9b8b959c9c1f6e761ab8d
 F src/expr.c 6d5f2c38fe3ec06a7eac599dac822788b36064124e20112a844e9cd5156cb239
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 849049c74a4c68961154c124087b5c67d277217a2e642570d0c1bd6336859940
@@ -2205,8 +2205,8 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P b249516f6a6650808e035ec219e762bf24dcb7c32a6235984b995d08d07d35d8
-R 5330111931e3ecff89186b5f2d6b0982
+P 3995c45fff0e4bd10bcf49cc16eb1050216426723c63ba56d3ae5ba738c34019
+R 652ce342076e266e8f982c0969e3c6bc
 U drh
-Z d58fa1c081ceed524dfd09ccfa304c4e
+Z ae5f81dac74fb395c307223c199b02f0
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 0ffd5cf0fb..fa4bad2218 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-3995c45fff0e4bd10bcf49cc16eb1050216426723c63ba56d3ae5ba738c34019
+bc5f5ce59e1e4323422bda7d002310923f927a03b4fd42749bf04f6c9853956b
diff --git a/src/delete.c b/src/delete.c
index 010a900191..1aa67c6a62 100644
--- a/src/delete.c
+++ b/src/delete.c
@@ -24,7 +24,7 @@
 **
 ** The following fields are initialized appropriate in pSrc:
 **
-**    pSrc->a[0].pTab       Pointer to the Table object
+**    pSrc->a[0].spTab      Pointer to the Table object
 **    pSrc->a[0].pIndex     Pointer to the INDEXED BY index, if there is one
 **
 */
@@ -219,7 +219,7 @@ Expr *sqlite3LimitWhere(
   **   );
   */
 
-  pTab = pSrc->a[0].pTab;
+  pTab = pSrc->a[0].pSTab;
   if( HasRowid(pTab) ){
     pLhs = sqlite3PExpr(pParse, TK_ROW, 0, 0);
     pEList = sqlite3ExprListAppend(
@@ -252,9 +252,9 @@ Expr *sqlite3LimitWhere(
 
   /* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree
   ** and the SELECT subtree. */
-  pSrc->a[0].pTab = 0;
+  pSrc->a[0].pSTab = 0;
   pSelectSrc = sqlite3SrcListDup(db, pSrc, 0);
-  pSrc->a[0].pTab = pTab;
+  pSrc->a[0].pSTab = pTab;
   if( pSrc->a[0].fg.isIndexedBy ){
     assert( pSrc->a[0].fg.isCte==0 );
     pSrc->a[0].u2.pIBIndex = 0;

From 692c160360c688c4bee3dd13d5293f2c416ad92f Mon Sep 17 00:00:00 2001
From: drh <>
Date: Tue, 20 Aug 2024 19:09:59 +0000
Subject: [PATCH 07/10] Tighter checking of access constraints on union members
 in SrcItem. Improved invariant checking.

FossilOrigin-Name: fd72d3400a8fe5747f494eee81654698acee350bb95b9db269e87d857af03492
---
 manifest        | 24 ++++++++++++------------
 manifest.uuid   |  2 +-
 src/build.c     | 11 ++++++++++-
 src/delete.c    |  2 +-
 src/fkey.c      |  2 +-
 src/insert.c    |  1 +
 src/select.c    |  4 ++++
 src/sqliteInt.h | 30 +++++++++++++++++-------------
 src/trigger.c   |  6 ++++--
 9 files changed, 51 insertions(+), 31 deletions(-)

diff --git a/manifest b/manifest
index 614e098984..298d9f0ab3 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\ssome\sstray\sSrcItem\sfield\sname\sfixes.
-D 2024-08-20T17:41:44.355
+C Tighter\schecking\sof\saccess\sconstraints\son\sunion\smembers\sin\sSrcItem.\nImproved\sinvariant\schecking.
+D 2024-08-20T19:09:59.313
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -702,24 +702,24 @@ F src/btmutex.c 79a43670447eacc651519a429f6ece9fd638563cf95b469d6891185ddae2b522
 F src/btree.c 8b42fc7d9efdb2df05c30e8f91ff6cfbd979724ae24bf90269028468b7a13333
 F src/btree.h 55066f513eb095db935169dab1dc2f7c7a747ef223c533f5d4ad4dfed346cbd0
 F src/btreeInt.h 98aadb6dcb77b012cab2574d6a728fad56b337fc946839b9898c4b4c969e30b6
-F src/build.c 29ebc26d90a9d6e860a3018a6d61fb667c80ec8e80e3798c4164d2349ba28650
+F src/build.c 69d79a255a6a0547f5e99a1726c3cbd363fa221c4f0458425abc7ba59efb9f83
 F src/callback.c db3a45e376deff6a16c0058163fe0ae2b73a2945f3f408ca32cf74960b28d490
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 64e4b1227b4ed123146f0aa2989131d1fbd9b927b11e80c9d58c6a68f9cd5ce3
 F src/date.c 13dd752847afb32ed70510ad7345a5b9c841f51ad904dba5d010f1fa3a6a324e
 F src/dbpage.c 80e46e1df623ec40486da7a5086cb723b0275a6e2a7b01d9f9b5da0f04ba2782
 F src/dbstat.c 3b677254d512fcafd4d0b341bf267b38b235ccfddbef24f9154e19360fa22e43
-F src/delete.c 3638367ea4ed5d422ee1728a74f0b7a2973af9d7eef9b8b959c9c1f6e761ab8d
+F src/delete.c cfe1a09cd67e3c8aef51ef928c69ba2824e6e2439f451e990afbb89e774add01
 F src/expr.c 6d5f2c38fe3ec06a7eac599dac822788b36064124e20112a844e9cd5156cb239
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
-F src/fkey.c 849049c74a4c68961154c124087b5c67d277217a2e642570d0c1bd6336859940
+F src/fkey.c 928ed2517e8732113d2b9821aa37af639688d752f4ea9ac6e0e393d713eeb76f
 F src/func.c 1f61e32e7a357e615b5d2e774bee563761fce4f2fd97ecb0f72c33e62a2ada5f
 F src/global.c 61a419dd9e993b9be0f91de4c4ccf322b053eb829868e089f0321dd669be3b90
 F src/hash.c 9ee4269fb1d6632a6fecfb9479c93a1f29271bddbbaf215dd60420bcb80c7220
 F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
 F src/hwtime.h f9c2dfb84dce7acf95ce6d289e46f5f9d3d1afd328e53da8f8e9008e3b3caae6
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
-F src/insert.c 37c0c12c6eea72c4dad77699b963be370ca6cbd7d18270ff04f5fe9d6031622d
+F src/insert.c f8d1a0f8ee258411009c6b7f2d93170e351bd19f5ad89d57e1180644297cbe70
 F src/json.c 5b6a1d6015997b9ee848a32948720bdb26a0ef2de5a2127ebf7355ce66dbdc0d
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 7432c944ff197046d67a1207790a1b13eec4548c85a9457eb0896bb3641dfb36
@@ -760,12 +760,12 @@ F src/printf.c 17054fb94ffcf7a28362e9a5af4a0f813bd0c52200ae408eeebddc81feed9274
 F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
 F src/resolve.c 9afed5fd7b9111633bdb74a73cdc47324e28e4dc6c27113e3e9aee38fb9422ab
 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97
-F src/select.c 9aa44e562f2fbfa33e600e3f935369dd9a07e4beb89b344dfc7187dc2adc19ce
+F src/select.c 7addcd53d8f9bef2d47a7e47faeb1f6e401dba02f1f338f532298a24657ea4e6
 F src/shell.c.in 94571558b0fb28c37a5cf6dbd6ea27285341023a28a8cb5795cd2768fab67704
 F src/sqlite.h.in 1ad9110150773c38ebababbad11b5cb361bcd3997676dec1c91ac5e0416a7b86
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 3f046c04ea3595d6bfda99b781926b17e672fd6d27da2ba6d8d8fc39981dcb54
-F src/sqliteInt.h 630e356b7d94df1dcbc32d4f7d4569725a12c6de014fe064311219c22d9cbd54
+F src/sqliteInt.h 521a9abd808e2b6c2e377cfc85b5ad5508202c33f878f929dccf60d6aca13034
 F src/sqliteLimit.h 6878ab64bdeb8c24a1d762d45635e34b96da21132179023338c93f820eee6728
 F src/status.c cb11f8589a6912af2da3bb1ec509a94dd8ef27df4d4c1a97e0bcf2309ece972b
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -825,7 +825,7 @@ F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
 F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
 F src/tokenize.c 3f703cacdab728d7741e5a6ac242006d74fe1c2754d4f03ed889d7253259bd68
 F src/treeview.c e98dbc8068d27f3d0bd2a4cebfce6a7c21c776edc23d80e12c67a70cd2ba3fe5
-F src/trigger.c 68d849ea6ccab67beb450d1a0d065c6118f0884a779388b07f0d9a27dbda38c9
+F src/trigger.c 0bb986a5b96047fd597c6aac28588853df56064e576e6b81ba777ef2ccaac461
 F src/update.c 0e01aa6a3edf9ec112b33eb714b9016a81241497b1fb7c3e74332f4f71756508
 F src/upsert.c 215328c3f91623c520ec8672c44323553f12caeb4f01b1090ebdca99fdf7b4f1
 F src/utf.c f23165685a67b4caf8ec08fb274cb3f319103decfb2a980b7cfd55d18dfa855e
@@ -2205,8 +2205,8 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 3995c45fff0e4bd10bcf49cc16eb1050216426723c63ba56d3ae5ba738c34019
-R 652ce342076e266e8f982c0969e3c6bc
+P bc5f5ce59e1e4323422bda7d002310923f927a03b4fd42749bf04f6c9853956b
+R ee08ce1ecc132f8a5f905e65ae160cc1
 U drh
-Z ae5f81dac74fb395c307223c199b02f0
+Z 01685802d904a82a17f4e5855c564d7e
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index fa4bad2218..06a9d2670a 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-bc5f5ce59e1e4323422bda7d002310923f927a03b4fd42749bf04f6c9853956b
+fd72d3400a8fe5747f494eee81654698acee350bb95b9db269e87d857af03492
diff --git a/src/build.c b/src/build.c
index 9cbedf1ec4..b2386035d8 100644
--- a/src/build.c
+++ b/src/build.c
@@ -501,6 +501,7 @@ Table *sqlite3LocateTableItem(
     int iDb = sqlite3SchemaToIndex(pParse->db, p->u4.pSchema);
     zDb = pParse->db->aDb[iDb].zDbSName;
   }else{
+    assert( !p->fg.isSubquery );
     zDb = p->u4.zDatabase;
   }
   return sqlite3LocateTable(pParse, flags, p->zName, zDb);
@@ -3487,6 +3488,7 @@ void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
   assert( pParse->nErr==0 );
   assert( pName->nSrc==1 );
   assert( pName->a[0].fg.fixedSchema==0 );
+  assert( pName->a[0].fg.isSubquery==0 );
   if( sqlite3ReadSchema(pParse) ) goto exit_drop_table;
   if( noErr ) db->suppressErr++;
   assert( isView==0 || isView==LOCATE_VIEW );
@@ -4587,6 +4589,7 @@ void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists){
   assert( pParse->nErr==0 );   /* Never called with prior non-OOM errors */
   assert( pName->nSrc==1 );
   assert( pName->a[0].fg.fixedSchema==0 );
+  assert( pName->a[0].fg.isSubquery==0 );
   if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
     goto exit_drop_index;
   }
@@ -4893,6 +4896,7 @@ SrcList *sqlite3SrcListAppend(
     pDatabase = 0;
   }
   assert( pItem->fg.fixedSchema==0 );
+  assert( pItem->fg.isSubquery==0 );
   if( pDatabase ){
     pItem->zName = sqlite3NameFromToken(db, pDatabase);
     pItem->u4.zDatabase = sqlite3NameFromToken(db, pTable);
@@ -4959,8 +4963,13 @@ void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
   for(pItem=pList->a, i=0; i<pList->nSrc; i++, pItem++){
  
     /* Check invariants on SrcItem */
+    assert( !pItem->fg.isIndexedBy || !pItem->fg.isTabFunc );
+    assert( !pItem->fg.isCte || !pItem->fg.isIndexedBy );
     assert( !pItem->fg.hadSchema || !pItem->fg.isSubquery );
-    assert( pItem->fg.hadSchema==0 || pItem->fg.fixedSchema==1 );
+    assert( !pItem->fg.hadSchema || pItem->fg.fixedSchema );
+    assert( !pItem->fg.fixedSchema || !pItem->fg.isSubquery );
+    assert( !pItem->fg.isSubquery || (pItem->u4.pSubq!=0 && 
+                                      pItem->u4.pSubq->pSelect!=0) );
 
     if( pItem->zName ) sqlite3DbNNFreeNN(db, pItem->zName);
     if( pItem->zAlias ) sqlite3DbNNFreeNN(db, pItem->zAlias);
diff --git a/src/delete.c b/src/delete.c
index 1aa67c6a62..1d7ba66a22 100644
--- a/src/delete.c
+++ b/src/delete.c
@@ -156,7 +156,7 @@ void sqlite3MaterializeView(
   if( pFrom ){
     assert( pFrom->nSrc==1 );
     pFrom->a[0].zName = sqlite3DbStrDup(db, pView->zName);
-    assert( pFrom->a[0].fg.fixedSchema==0 );
+    assert( pFrom->a[0].fg.fixedSchema==0 && pFrom->a[0].fg.isSubquery==0 );
     pFrom->a[0].u4.zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
     assert( pFrom->a[0].fg.isUsing==0 );
     assert( pFrom->a[0].u3.pOn==0 );
diff --git a/src/fkey.c b/src/fkey.c
index cd1f88502e..f1117a8845 100644
--- a/src/fkey.c
+++ b/src/fkey.c
@@ -1337,7 +1337,7 @@ static Trigger *fkActionTrigger(
       if( pSrc ){
         assert( pSrc->nSrc==1 );
         pSrc->a[0].zName = sqlite3DbStrDup(db, zFrom);
-        assert( pSrc->a[0].fg.fixedSchema==0 );
+        assert( pSrc->a[0].fg.fixedSchema==0 && pSrc->a[0].fg.isSubquery==0 );
         pSrc->a[0].u4.zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
       }
       pSelect = sqlite3SelectNew(pParse, 
diff --git a/src/insert.c b/src/insert.c
index 8214cd9c5c..d380281bed 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -729,6 +729,7 @@ Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow){
         p = &pRet->pSrc->a[0];
         p->fg.viaCoroutine = 1;
         p->iCursor = -1;
+        assert( !p->fg.isIndexedBy && !p->fg.isTabFunc );
         p->u1.nRow = 2;
         if( sqlite3SrcItemAttachSubquery(pParse, p, pLeft, 0) ){
           pSubq = p->u4.pSubq;
diff --git a/src/select.c b/src/select.c
index 0c10550fac..39955dd60a 100644
--- a/src/select.c
+++ b/src/select.c
@@ -4522,6 +4522,7 @@ static int flattenSubquery(
   }else{
     pSub1 = 0;
   }
+  assert( pSubitem->fg.isSubquery==0 );
   if( pSubitem->fg.fixedSchema==0 ){
     sqlite3DbFree(db, pSubitem->u4.zDatabase);
     pSubitem->u4.zDatabase = 0;
@@ -5812,6 +5813,7 @@ static int resolveFromTermToCte(
       sqlite3ErrorMsg(pParse, "no such index: \"%s\"", pFrom->u1.zIndexedBy);
       return 2;
     }
+    assert( !pFrom->fg.isIndexedBy );
     pFrom->fg.isCte = 1;
     pFrom->u2.pCteUse = pCteUse;
     pCteUse->nUse++;
@@ -7728,6 +7730,8 @@ int sqlite3Select(
       if( pItem->fg.fixedSchema ){
         int iDb = sqlite3SchemaToIndex(pParse->db, pItem->u4.pSchema);
         zDb = db->aDb[iDb].zDbSName;
+      }else if( pItem->fg.isSubquery ){
+        zDb = 0;
       }else{
         zDb = pItem->u4.zDatabase;
       }
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index c282023de4..9e0faf9cc1 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3298,26 +3298,30 @@ struct Subquery {
 ** In the colUsed field, the high-order bit (bit 63) is set if the table
 ** contains more than 63 columns and the 64-th or later column is used.
 **
-** Intenstive use of "union" helps keep the size of the object small.  This
-** has been shown to boost performance due to less time spend initializing
-** fields to zero when a new instance of this object is allocated.  The unions
-** also help SrcItem, and hence SrcList and Select, use less memory.
-**
-** Union member validity:
+** Aggressive use of "union" helps keep the size of the object small.  This
+** has been shown to boost performance, in addition to saving memory.
+** Access to union elements is gated by the following rules which should
+** always be checked, either by an if-statement or by an assert().
 **
+**    Field              Only access if this is true
+**    ---------------    -----------------------------------
 **    u1.zIndexedBy      fg.isIndexedBy
 **    u1.pFuncArg        fg.isTabFunc
 **    u1.nRow            !fg.isTabFunc  && !fg.isIndexedBy
 **
-**    u2.pIBIndex        fg.isIndexedBy && !fg.isCte
-**    u2.pCteUse         fg.isCte       && !fg.isIndexedBy
+**    u2.pIBIndex        fg.isIndexedBy
+**    u2.pCteUse         fg.isCte
 **
-**    u3.pOn             fg.isUsing==0
-**    u3.pUsing          fg.isUsing==1
+**    u3.pOn             !fg.isUsing
+**    u3.pUsing          fg.isUsing
 **
-**    u4.zDatabase       fg.fixedSchema==0 && !fg.isSubquery
-**    u4.pSchema         fg.fixedSchema==1
+**    u4.zDatabase       !fg.fixedSchema && !fg.isSubquery
+**    u4.pSchema         fg.fixedSchema
 **    u4.pSubq           fg.isSubquery
+**
+** See also the sqlite3SrcListDelete() routine for assert() statements that
+** check invariants on the fields of this object, especially the flags
+** inside the fg struct.
 */
 struct SrcItem {
   char *zName;      /* Name of the table */
@@ -3342,7 +3346,7 @@ struct SrcItem {
     unsigned isNestedFrom :1;  /* pSelect is a SF_NestedFrom subquery */
     unsigned rowidUsed :1;     /* The ROWID of this table is referenced */
     unsigned fixedSchema :1;   /* Uses u4.pSchema, not u4.zDatabase */
-    unsigned hadSchema :1;     /* Has u4.zDatabase before u4.pSchema */
+    unsigned hadSchema :1;     /* Had u4.zDatabase before u4.pSchema */
   } fg;
   int iCursor;      /* The VDBE cursor number used to access this table */
   Bitmask colUsed;  /* Bit N set if column N used. Details above for N>62 */
diff --git a/src/trigger.c b/src/trigger.c
index 170f094eab..ff2df82cbc 100644
--- a/src/trigger.c
+++ b/src/trigger.c
@@ -151,7 +151,9 @@ void sqlite3BeginTrigger(
   ** To maintain backwards compatibility, ignore the database
   ** name on pTableName if we are reparsing out of the schema table
   */
-  if( db->init.busy && iDb!=1 && ALWAYS(pTableName->a[0].fg.fixedSchema==0) ){
+  if( db->init.busy && iDb!=1 ){
+    assert( pTableName->a[0].fg.fixedSchema==0 );
+    assert( pTableName->a[0].fg.isSubquery==0 );
     sqlite3DbFree(db, pTableName->a[0].u4.zDatabase);
     pTableName->a[0].u4.zDatabase = 0;
   }
@@ -631,7 +633,7 @@ void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
   }
 
   assert( pName->nSrc==1 );
-  assert( pName->a[0].fg.fixedSchema==0 );
+  assert( pName->a[0].fg.fixedSchema==0 && pName->a[0].fg.isSubquery==0 );
   zDb = pName->a[0].u4.zDatabase;
   zName = pName->a[0].zName;
   assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) );

From 0766cbf51157671e39e9109303bf315c661616ac Mon Sep 17 00:00:00 2001
From: drh <>
Date: Tue, 20 Aug 2024 20:01:21 +0000
Subject: [PATCH 08/10] Remove unreachable code.

FossilOrigin-Name: 17699329aa8e234c6793a38db5ca05def9395b287bcc8bc05493b824327edb59
---
 manifest      | 18 +++++++++---------
 manifest.uuid |  2 +-
 src/build.c   |  2 +-
 src/parse.y   |  5 ++---
 src/printf.c  |  4 +---
 src/select.c  |  6 +-----
 6 files changed, 15 insertions(+), 22 deletions(-)

diff --git a/manifest b/manifest
index 298d9f0ab3..347a5b8ce1 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Tighter\schecking\sof\saccess\sconstraints\son\sunion\smembers\sin\sSrcItem.\nImproved\sinvariant\schecking.
-D 2024-08-20T19:09:59.313
+C Remove\sunreachable\scode.
+D 2024-08-20T20:01:21.013
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -702,7 +702,7 @@ F src/btmutex.c 79a43670447eacc651519a429f6ece9fd638563cf95b469d6891185ddae2b522
 F src/btree.c 8b42fc7d9efdb2df05c30e8f91ff6cfbd979724ae24bf90269028468b7a13333
 F src/btree.h 55066f513eb095db935169dab1dc2f7c7a747ef223c533f5d4ad4dfed346cbd0
 F src/btreeInt.h 98aadb6dcb77b012cab2574d6a728fad56b337fc946839b9898c4b4c969e30b6
-F src/build.c 69d79a255a6a0547f5e99a1726c3cbd363fa221c4f0458425abc7ba59efb9f83
+F src/build.c c5522b5faf8128227678e194275cefaeb4d063f55dbe70bcff745f1b63a187cf
 F src/callback.c db3a45e376deff6a16c0058163fe0ae2b73a2945f3f408ca32cf74960b28d490
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 64e4b1227b4ed123146f0aa2989131d1fbd9b927b11e80c9d58c6a68f9cd5ce3
@@ -749,18 +749,18 @@ F src/os_win.c 6ff43bac175bd9ed79e7c0f96840b139f2f51d01689a638fd05128becf94908a
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
 F src/pager.c b08600ebf0db90b6d1e9b8b6577c6fa3877cbe1a100bd0b2899e4c6e9adad4b3
 F src/pager.h 4b1140d691860de0be1347474c51fee07d5420bd7f802d38cbab8ea4ab9f538a
-F src/parse.y 967e0a712de8bee4b2cf82bd9efa36b68afd03cc486d4ea77a945feb49b057dc
+F src/parse.y 5972b7d00af4c8d96fdad781af1ea1d5d51fc3b907ad61bda60e49503274e5ed
 F src/pcache.c 588cc3c5ccaaadde689ed35ce5c5c891a1f7b1f4d1f56f6cf0143b74d8ee6484
 F src/pcache.h 1497ce1b823cf00094bb0cf3bac37b345937e6f910890c626b16512316d3abf5
 F src/pcache1.c 49516ad7718a3626f28f710fa7448ef1fce3c07fd169acbb4817341950264319
 F src/pragma.c 52bfbf6dfd668b69b5eb9bd1186e3a67367c8453807150d6e75239229924f684
 F src/pragma.h e690a356c18e98414d2e870ea791c1be1545a714ba623719deb63f7f226d8bb7
 F src/prepare.c d99931f45416652895e502328ca49fe782cfc4e1ebdcda13b3736d991ebf42ce
-F src/printf.c 17054fb94ffcf7a28362e9a5af4a0f813bd0c52200ae408eeebddc81feed9274
+F src/printf.c 6a87534ebfb9e5346011191b1f3a7ebc457f5938c7e4feeea478ecf53f6a41b2
 F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
 F src/resolve.c 9afed5fd7b9111633bdb74a73cdc47324e28e4dc6c27113e3e9aee38fb9422ab
 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97
-F src/select.c 7addcd53d8f9bef2d47a7e47faeb1f6e401dba02f1f338f532298a24657ea4e6
+F src/select.c 6f1651ca254a6856c2ec5b8a0188bc226e7a454d6741d3f71ebcd631ce147807
 F src/shell.c.in 94571558b0fb28c37a5cf6dbd6ea27285341023a28a8cb5795cd2768fab67704
 F src/sqlite.h.in 1ad9110150773c38ebababbad11b5cb361bcd3997676dec1c91ac5e0416a7b86
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -2205,8 +2205,8 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P bc5f5ce59e1e4323422bda7d002310923f927a03b4fd42749bf04f6c9853956b
-R ee08ce1ecc132f8a5f905e65ae160cc1
+P fd72d3400a8fe5747f494eee81654698acee350bb95b9db269e87d857af03492
+R ed1ab5c9cb5cf9505f2201c6b302f119
 U drh
-Z 01685802d904a82a17f4e5855c564d7e
+Z 40ddef7af9ce2e2b1803942ebd50a97a
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 06a9d2670a..33f57517e4 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-fd72d3400a8fe5747f494eee81654698acee350bb95b9db269e87d857af03492
+17699329aa8e234c6793a38db5ca05def9395b287bcc8bc05493b824327edb59
diff --git a/src/build.c b/src/build.c
index b2386035d8..74577ed0d5 100644
--- a/src/build.c
+++ b/src/build.c
@@ -5012,7 +5012,7 @@ int sqlite3SrcItemAttachSubquery(
   int dupSelect      /* If true, attach a copy of pSelect, not pSelect itself.*/
 ){
   Subquery *p;
-  if( pSelect==0 ) return SQLITE_OK;
+  assert( pSelect!=0 );
   assert( pItem->fg.isSubquery==0 );
   if( pItem->fg.fixedSchema ){
     pItem->u4.pSchema = 0;
diff --git a/src/parse.y b/src/parse.y
index a47c587547..926dd6e7d1 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -748,9 +748,8 @@ seltablist(A) ::= stl_prefix(A) nm(Y) dbnm(D) LP exprlist(E) RP as(Z) on_using(N
           pNew->u4.pSubq = pOld->u4.pSubq;
           pOld->u4.pSubq = 0;
           pOld->fg.isSubquery = 0;
-          if( pNew->u4.pSubq->pSelect
-           && (pNew->u4.pSubq->pSelect->selFlags & SF_NestedFrom)!=0
-          ){
+          assert( pNew->u4.pSubq!=0 && pNew->u4.pSubq->pSelect!=0 );
+          if( (pNew->u4.pSubq->pSelect->selFlags & SF_NestedFrom)!=0 ){
             pNew->fg.isNestedFrom = 1;
           }
         }else{
diff --git a/src/printf.c b/src/printf.c
index be7ffc8c76..a140565146 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -858,7 +858,7 @@ void sqlite3_str_vappendf(
           sqlite3_str_appendall(pAccum, pItem->zName);
         }else if( pItem->zAlias ){
           sqlite3_str_appendall(pAccum, pItem->zAlias);
-        }else if( pItem->fg.isSubquery ){/* Because of tag-20240424-1 */
+        }else if( ALWAYS(pItem->fg.isSubquery) ){/* Because of tag-20240424-1 */
           Select *pSel = pItem->u4.pSubq->pSelect;
           assert( pSel!=0 ); 
           if( pSel->selFlags & SF_NestedFrom ){
@@ -870,8 +870,6 @@ void sqlite3_str_vappendf(
           }else{
             sqlite3_str_appendf(pAccum, "(subquery-%u)", pSel->selId);
           }
-        }else{
-          sqlite3_str_appendf(pAccum, "(unknown-data-source-%p)", pItem);
         }
         length = width = 0;
         break;
diff --git a/src/select.c b/src/select.c
index 39955dd60a..655221b067 100644
--- a/src/select.c
+++ b/src/select.c
@@ -4523,10 +4523,7 @@ static int flattenSubquery(
     pSub1 = 0;
   }
   assert( pSubitem->fg.isSubquery==0 );
-  if( pSubitem->fg.fixedSchema==0 ){
-    sqlite3DbFree(db, pSubitem->u4.zDatabase);
-    pSubitem->u4.zDatabase = 0;
-  }
+  assert( pSubitem->fg.fixedSchema==0 );
   sqlite3DbFree(db, pSubitem->zName);
   sqlite3DbFree(db, pSubitem->zAlias);
   pSubitem->zName = 0;
@@ -5601,7 +5598,6 @@ static int convertCompoundSelectToSubquery(Walker *pWalker, Select *p){
   /* If we reach this point, that means the transformation is required. */
 
   pParse = pWalker->pParse;
-  if( pParse->nErr ) return WRC_Abort;
   db = pParse->db;
   pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
   if( pNew==0 ) return WRC_Abort;

From bb36d55e638fb7f8ba1c1ce787b835f398fc98d3 Mon Sep 17 00:00:00 2001
From: drh <>
Date: Tue, 20 Aug 2024 22:05:01 +0000
Subject: [PATCH 09/10] Fix minor comment issues.

FossilOrigin-Name: c1bbed19f4348ec31c3cb4723eaa8f1554bb58ef4de7feb3a0f39612785f13d5
---
 manifest        | 14 +++++++-------
 manifest.uuid   |  2 +-
 src/delete.c    |  4 ++--
 src/sqliteInt.h |  2 +-
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/manifest b/manifest
index 347a5b8ce1..72fecdb486 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Remove\sunreachable\scode.
-D 2024-08-20T20:01:21.013
+C Fix\sminor\scomment\sissues.
+D 2024-08-20T22:05:01.213
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -709,7 +709,7 @@ F src/ctime.c 64e4b1227b4ed123146f0aa2989131d1fbd9b927b11e80c9d58c6a68f9cd5ce3
 F src/date.c 13dd752847afb32ed70510ad7345a5b9c841f51ad904dba5d010f1fa3a6a324e
 F src/dbpage.c 80e46e1df623ec40486da7a5086cb723b0275a6e2a7b01d9f9b5da0f04ba2782
 F src/dbstat.c 3b677254d512fcafd4d0b341bf267b38b235ccfddbef24f9154e19360fa22e43
-F src/delete.c cfe1a09cd67e3c8aef51ef928c69ba2824e6e2439f451e990afbb89e774add01
+F src/delete.c 444c4d1eaac40103461e3b6f0881846dd3aafc1cec1dd169d3482fa331667da7
 F src/expr.c 6d5f2c38fe3ec06a7eac599dac822788b36064124e20112a844e9cd5156cb239
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 928ed2517e8732113d2b9821aa37af639688d752f4ea9ac6e0e393d713eeb76f
@@ -765,7 +765,7 @@ F src/shell.c.in 94571558b0fb28c37a5cf6dbd6ea27285341023a28a8cb5795cd2768fab6770
 F src/sqlite.h.in 1ad9110150773c38ebababbad11b5cb361bcd3997676dec1c91ac5e0416a7b86
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 3f046c04ea3595d6bfda99b781926b17e672fd6d27da2ba6d8d8fc39981dcb54
-F src/sqliteInt.h 521a9abd808e2b6c2e377cfc85b5ad5508202c33f878f929dccf60d6aca13034
+F src/sqliteInt.h 28c878bdf528879afefe1994ac007d094f8061f2fdacdc55d6055d7e9341151e
 F src/sqliteLimit.h 6878ab64bdeb8c24a1d762d45635e34b96da21132179023338c93f820eee6728
 F src/status.c cb11f8589a6912af2da3bb1ec509a94dd8ef27df4d4c1a97e0bcf2309ece972b
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -2205,8 +2205,8 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P fd72d3400a8fe5747f494eee81654698acee350bb95b9db269e87d857af03492
-R ed1ab5c9cb5cf9505f2201c6b302f119
+P 17699329aa8e234c6793a38db5ca05def9395b287bcc8bc05493b824327edb59
+R 0e51c42305c6bc1152097a45ebccdb0d
 U drh
-Z 40ddef7af9ce2e2b1803942ebd50a97a
+Z a6fa404293297d6b35cfa7a7af20f07b
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 33f57517e4..b77c8e18bf 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-17699329aa8e234c6793a38db5ca05def9395b287bcc8bc05493b824327edb59
+c1bbed19f4348ec31c3cb4723eaa8f1554bb58ef4de7feb3a0f39612785f13d5
diff --git a/src/delete.c b/src/delete.c
index 1d7ba66a22..4cdb3946e3 100644
--- a/src/delete.c
+++ b/src/delete.c
@@ -24,8 +24,8 @@
 **
 ** The following fields are initialized appropriate in pSrc:
 **
-**    pSrc->a[0].spTab      Pointer to the Table object
-**    pSrc->a[0].pIndex     Pointer to the INDEXED BY index, if there is one
+**    pSrc->a[0].spTab        Pointer to the Table object
+**    pSrc->a[0].u2.pIBIndex  Pointer to the INDEXED BY index, if there is one
 **
 */
 Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 9e0faf9cc1..d1ffce6d87 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3627,7 +3627,7 @@ struct Select {
 #define SF_UpdateFrom   0x10000000 /* Query originates with UPDATE FROM */
 #define SF_Correlated   0x20000000 /* True if references the outer context */
 
-/* True if SrcList item X is a subquery that has SF_NestedFrom */
+/* True if SrcItem X is a subquery that has SF_NestedFrom */
 #define IsNestedFrom(X) \
    ((X)->fg.isSubquery && \
     ((X)->u4.pSubq->pSelect->selFlags&SF_NestedFrom)!=0)

From a0651b370706e58f9014453c5f36124ca8a738c9 Mon Sep 17 00:00:00 2001
From: drh <>
Date: Tue, 20 Aug 2024 22:44:40 +0000
Subject: [PATCH 10/10] Fix a name resolution issue with CTEs.

FossilOrigin-Name: 4fa8235dd59cd683d6c6c97bfe181a9637be7c054d435323c903b9dbd74aff02
---
 manifest        | 14 +++++++-------
 manifest.uuid   |  2 +-
 src/select.c    |  7 ++++---
 test/with2.test | 11 ++++++++++-
 4 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/manifest b/manifest
index 72fecdb486..7ee60fbf49 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sminor\scomment\sissues.
-D 2024-08-20T22:05:01.213
+C Fix\sa\sname\sresolution\sissue\swith\sCTEs.
+D 2024-08-20T22:44:40.653
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -760,7 +760,7 @@ F src/printf.c 6a87534ebfb9e5346011191b1f3a7ebc457f5938c7e4feeea478ecf53f6a41b2
 F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
 F src/resolve.c 9afed5fd7b9111633bdb74a73cdc47324e28e4dc6c27113e3e9aee38fb9422ab
 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97
-F src/select.c 6f1651ca254a6856c2ec5b8a0188bc226e7a454d6741d3f71ebcd631ce147807
+F src/select.c c1c28650d3ea5dc0670dd658600b963c29a5c31b685941a5df583b02631d04ff
 F src/shell.c.in 94571558b0fb28c37a5cf6dbd6ea27285341023a28a8cb5795cd2768fab67704
 F src/sqlite.h.in 1ad9110150773c38ebababbad11b5cb361bcd3997676dec1c91ac5e0416a7b86
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -2070,7 +2070,7 @@ F test/windowerr.test a8b752402109c15aa1c5efe1b93ccb0ce1ef84fa964ae1cd6684dd0b3c
 F test/windowfault.test 15094c1529424e62f798bc679e3fe9dfab6e8ba2f7dfe8c923b6248c31660a7c
 F test/windowpushd.test c420e2265f0e09a0e798d0513a660d71b51602088d81b3dbd038918ee1339dcc
 F test/with1.test b93833890e5d2a368e78747f124503a0159aa029b98e9ed4795ebf630b2efd3d
-F test/with2.test 5885f0ef250504096ea4c0c6350ef2f2ab09b9e2dc2bc691e182f773db3aabb2
+F test/with2.test 181674a6cc86a601ca2ac052741cdfad5b529e07e870435d2f6cdb92d589ff17
 F test/with3.test e30369ea27aa27eb1bda4c5e510c8a9f782c8afd2ab99d1a02b8a7f25a5d3e65
 F test/with4.test 257be66c0c67fee1defbbac0f685c3465e2cad037f21ce65f23f86084f198205
 F test/with5.test 6248213c41fab36290b5b73aa3f937309dfba337004d9d8434c3fabc8c7d4be8
@@ -2205,8 +2205,8 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 17699329aa8e234c6793a38db5ca05def9395b287bcc8bc05493b824327edb59
-R 0e51c42305c6bc1152097a45ebccdb0d
+P c1bbed19f4348ec31c3cb4723eaa8f1554bb58ef4de7feb3a0f39612785f13d5
+R 1c80ace1a0877505f5ca5ebb5b98295b
 U drh
-Z a6fa404293297d6b35cfa7a7af20f07b
+Z ef82496d97c0311a270f63ff1146b092
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index b77c8e18bf..53632b3479 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-c1bbed19f4348ec31c3cb4723eaa8f1554bb58ef4de7feb3a0f39612785f13d5
+4fa8235dd59cd683d6c6c97bfe181a9637be7c054d435323c903b9dbd74aff02
diff --git a/src/select.c b/src/select.c
index 655221b067..b76e42b74c 100644
--- a/src/select.c
+++ b/src/select.c
@@ -5823,9 +5823,10 @@ static int resolveFromTermToCte(
       assert( pRecTerm->pPrior!=0 );
       for(i=0; i<pSrc->nSrc; i++){
         SrcItem *pItem = &pSrc->a[i];
-        if( ((pItem->fg.fixedSchema==0 && pItem->u4.zDatabase==0)
-             || pItem->fg.hadSchema==0)
-         && pItem->zName!=0
+        if( pItem->zName!=0
+         && !pItem->fg.hadSchema
+         && ALWAYS( !pItem->fg.isSubquery )
+         && (pItem->fg.fixedSchema || pItem->u4.zDatabase==0)
          && 0==sqlite3StrICmp(pItem->zName, pCte->zName)
         ){
           pItem->pSTab = pTab;
diff --git a/test/with2.test b/test/with2.test
index ad1753d659..68790fe860 100644
--- a/test/with2.test
+++ b/test/with2.test
@@ -146,7 +146,6 @@ do_execsql_test 1.14 {
   SELECT * FROM t4;
 } {4 5 6 7 8 9 10}
 
-exit
 do_execsql_test 1.15 {
   WITH 
   t4(x) AS ( 
@@ -157,6 +156,16 @@ do_execsql_test 1.15 {
   SELECT * FROM t4;
 } {4 5}
 
+do_execsql_test 1.15.2 {
+  WITH 
+  t4(x) AS ( 
+    VALUES(4)
+    UNION ALL 
+    SELECT x+1 FROM (SELECT * FROM main.t4) WHERE x<10
+  )
+  SELECT * FROM t4;
+} {4 5}
+
 do_catchsql_test 1.16 {
   WITH 
   t4(x) AS (