Walk back the optimization from check-in [cc458317bd77046c] that tries to

reuse the same ephemeral cursor of a list subquery when that subquery is
reused, as it does not work in cases where the list subquery is used both
for lookups and for scans.

FossilOrigin-Name: 12ee29d632ae4b585ef6bc07d3289d00c121268945dffd5673b251d95874e3f8

manifest

@@ -1,5 +1,5 @@
-C Defer\sgenerating\sWHERE\sclause\sconstraints\sfor\sa\sRIGHT\sJOIN\suntil\safter\sthe\nON-clause\sprocessing\sfor\sthe\sRIGHT\sJOIN\shas\sdone\sits\sown\srow\selimination.\nThis\sfixes\sand\sincorrect\soutput\sfrom\ssome\sRIGHT\sJOINs\sthat\swas\sidentified\nby\s[forum:/forumpost/41cc3851d864c5e6|forum\spost\s41cc3851d864c5e6].
-D 2022-05-13T17:45:52.976
+C Walk\sback\sthe\soptimization\sfrom\scheck-in\s[cc458317bd77046c]\sthat\stries\sto\nreuse\sthe\ssame\sephemeral\scursor\sof\sa\slist\ssubquery\swhen\sthat\ssubquery\sis\nreused,\sas\sit\sdoes\snot\swork\sin\scases\swhere\sthe\slist\ssubquery\sis\sused\sboth\nfor\slookups\sand\sfor\sscans.
+D 2022-05-13T19:50:29.681
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -504,7 +504,7 @@ F src/date.c 15082566229d4b1e5f24fdb490bf9bcc68824b911d70e3573ef075a1b9e2d26f
 F src/dbpage.c 90661a87e1db8bfbc8d2ebbdcd3749651ddb287c555c07a28fb17c7c591ffb68
 F src/dbstat.c 861e08690fcb0f2ee1165eff0060ea8d4f3e2ea10f80dab7d32ad70443a6ff2d
 F src/delete.c a8e844af211a48b13b5b358be77a12c860c6a557c21990ad51a548e2536500ce
-F src/expr.c d73ac75456ac14b1147eecc8c30bf08a0cb91b7f97c62632222a52f6222a9aa9
+F src/expr.c b4328d113e600cf99897d32d733b3db7e6c46689adf6745bd3a1d88f7eb4d613
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c d965ede15d8360c09ed59348940649ee647b192e784466837d7aefa836d1d91e
 F src/func.c a3407a6fbb0d4088d8d502e46f0ace63e0aeae7467ae23a9ca9815bbf9239761
@@ -558,7 +558,7 @@ F src/shell.c.in 176cad562152cbbafe7ecc9c83c82850e2c3d0cf33ec0a52d67341d35c842f2
 F src/sqlite.h.in 2a35f62185eb5e7ecc64a2f68442b538ce9be74f80f28a00abc24837edcf1c17
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h f49e28c25bd941e79794db5415fdf7b202deb3bc072ed6f1ed273d578703684e
-F src/sqliteInt.h 1f9e228f1b416536833913a8a1733f01a36e85f0330bbd90a0dd68f9a8613ee3
+F src/sqliteInt.h fbe2d12cc13e80ac88c69ecde5ef9f052025fba78aa10f3eed0c71a5302e9a76
 F src/sqliteLimit.h d7323ffea5208c6af2734574bae933ca8ed2ab728083caa117c9738581a31657
 F src/status.c 4a3da6d77eeb3531cb0dbdf7047772a2a1b99f98c69e90ce009c75fe6328b2c0
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -642,7 +642,7 @@ F src/wal.h c3aa7825bfa2fe0d85bef2db94655f99870a285778baa36307c0a16da32b226a
 F src/walker.c f890a3298418d7cba3b69b8803594fdc484ea241206a8dfa99db6dd36f8cbb3b
 F src/where.c d4d543f06b09ff8bac05072b015a2181f9c48561b1a146158aaaf09e40817567
 F src/whereInt.h 8da918f392bf202ccc0ee61291455b33ad171d209445f1ff3eaf62e0b6f6b363
-F src/wherecode.c 4ffa652982b8233b028bed36a4cb6d9293484e75b80f236772ff3c1a91816eca
+F src/wherecode.c 76e9d8e8ce50b58fbfabc4cea2e8e7205c4b6a94551c80d24f768009d2a68fc3
 F src/whereexpr.c efed370c684dce04eab949202c5452bbde993efb198de43c7a88f59411ad2a2c
 F src/window.c fff1b51757438c664e471d5184634e48dcdf8ea34b640f3b1b0810b1e06de18c
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
@@ -1148,7 +1148,7 @@ F test/join4.test 1a352e4e267114444c29266ce79e941af5885916
 F test/join5.test d22b6cba8fb59ab3f1c82701434c360705eb12d4ce200c449f37b018fc47681a
 F test/join6.test f809c025fa253f9e150c0e9afd4cef8813257bceeb6f46e04041228c9403cc2c
 F test/join7.test 8e72de4b45e5e930d18c305c7efe86015fb2552731e4e03ea226353036b0dab0
-F test/join8.test 9b83dc70b7e9f7d4ee0022a0fe44ec1858f103530c7eb253c10adb63aad16ec4
+F test/join8.test e736975960adc06e94eed24f2ba6eacf6a6026dbf42d67ed65c4afb2faca59d2
 F test/join9.test 9056ddd3b0c0f4f9d658f4521038d9a37dc23ead8ca9a505d0b0db2b6a471e05
 F test/joinA.test 7eab225dc1c1ab258a5e62513a4ed7cabbd3db971d59d5d92f4fb6fa14c12f6a
 F test/joinB.test 1b2ba3fc8568b49411787fccbf540570c148e9b6a53a30f80691cb6268098ded
@@ -1954,8 +1954,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 6f741d6cfb8831a3ac966257ac4519bcc8156293447bf50323c2d9b170125974
-R bc3436cf9c17c2665a43b91d0b429cda
+P 238d9c247cf69cc77fdb1af9d42ebe258610a533ac4204e2ddf8af17f24d18c4
+R 9a86ed9913b4ded0c8e7923e434811db
 U drh
-Z 7f18b62d8d1b8431770b8960ee426eac
+Z c59d4810013018d66fb5815f061f58db
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-238d9c247cf69cc77fdb1af9d42ebe258610a533ac4204e2ddf8af17f24d18c4
+12ee29d632ae4b585ef6bc07d3289d00c121268945dffd5673b251d95874e3f8

src/expr.c

@@ -2746,11 +2746,7 @@ int sqlite3FindInIndex(
 
   assert( pX->op==TK_IN );
   mustBeUnique = (inFlags & IN_INDEX_LOOP)!=0;
-  if( pX->iTable && (inFlags & IN_INDEX_REUSE_CUR)!=0 ){
-    iTab = pX->iTable;
-  }else{
-    iTab = pParse->nTab++;
-  }
+  iTab = pParse->nTab++;
 
   /* If the RHS of this IN(...) operator is a SELECT, and if it matters 
   ** whether or not the SELECT result contains NULL values, check whether

src/sqliteInt.h

@@ -5322,7 +5322,6 @@ const char *sqlite3JournalModename(int);
 #define IN_INDEX_NOOP_OK     0x0001  /* OK to return IN_INDEX_NOOP */
 #define IN_INDEX_MEMBERSHIP  0x0002  /* IN operator used for membership test */
 #define IN_INDEX_LOOP        0x0004  /* IN operator used as a loop */
-#define IN_INDEX_REUSE_CUR   0x0008  /* Reuse prior table cursor */
 int sqlite3FindInIndex(Parse *, Expr *, u32, int*, int*, int*);
 
 int sqlite3JournalOpen(sqlite3_vfs *, const char *, sqlite3_file *, int, int);

src/wherecode.c

@@ -623,8 +623,7 @@ static int codeEqualityTerm(
         sqlite3ExprDelete(db, pX);
       }else{
         aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*nEq);
-        eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP|IN_INDEX_REUSE_CUR,                                   0, aiMap,&iTab);
-        iTab = pExpr->iTable;
+        eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap, &iTab);
       }
       pX = pExpr;
     }

test/join8.test

@@ -283,4 +283,15 @@ do_execsql_test join8-8020 {
             JOIN t1 ON (t3.e IS NOT DISTINCT FROM t2.c);
 } {}
 
+# 2022-05-13 The idea of reusing subquery cursors does not
+# work, if the cursors are used both for scanning and lookups.
+#
+reset_db
+db null -
+do_execsql_test join8-9000 {
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b TEXT, c TEXT, d REAL);
+  INSERT INTO t1 VALUES(1,'E','bb',NULL),(2,NULL,NULL,NULL);
+  SELECT * FROM t1 NATURAL RIGHT JOIN t1 AS t2 WHERE (a,b) IN (SELECT a+0, b FROM t1);
+} {1 E bb -}
+
 finish_test