First cut at optimizing single-row updates to use a one-pass algorithm. (CVS 4973)

FossilOrigin-Name: fba97f7874d723111e873d1470fc1a95e64f922d

manifest

@@ -1,5 +1,5 @@
-C Add\sthree\snew\stest\scases\sto\sspeed4p.test.\s\sTwo\sof\sthe\sthree\sdo\ssingle-row\nupdates\sbased\son\srowid\sand\son\sprimary\skey.\s(CVS\s4972)
+C First\scut\sat\soptimizing\ssingle-row\supdates\sto\suse\sa\sone-pass\salgorithm.\s(CVS\s4973)
-D 2008-04-10T13:32:37
+D 2008-04-10T13:33:18
 F Makefile.arm-wince-mingw32ce-gcc ac5f7b2cef0cd850d6f755ba6ee4ab961b1fadf7
 F Makefile.in b861627d91df5ee422c54237aa38296954dc0151
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -135,12 +135,12 @@ F src/pragma.c e659c9e443d11854cff2fd250012365ae0ca81ba
 F src/prepare.c adc7e1fc08dfbab63cd213d4c0aff8f3fa70d477
 F src/printf.c 05d2b44d7b5b80c8a4a09108ddad9c20e254370d
 F src/random.c 2b2db2de4ab491f5a14d3480466f8f4b5a5db74a
-F src/select.c 53bfb7c4da43b2d20f27b5bf0ceab94d53835080
+F src/select.c 1abe53c844f536a79cc11b19127c8e6d47a87b20
 F src/server.c 087b92a39d883e3fa113cae259d64e4c7438bc96
 F src/shell.c 22297fffa6f00a6c6d44020fa13b1184a1bb372d
 F src/sqlite.h.in 5364513316e0c36cb02b27c479643b400dbde9c7
 F src/sqlite3ext.h faacd0e6a81aabee0861c6d7883c9172e74ef5b3
-F src/sqliteInt.h 0f571303e19ccd61b2112d9d2613cd36e2166e89
+F src/sqliteInt.h 52c381c2f15054a5199e5359cf5deb6d48624ede
 F src/sqliteLimit.h f435e728c6b620ef7312814d660a81f9356eb5c8
 F src/table.c 2c48c575dd59b3a6c5c306bc55f51a9402cf429a
 F src/tclsqlite.c d272cbd208f87712f67ae7462d2d6cffbb28a676
@@ -170,7 +170,7 @@ F src/test_tclvar.c b2d1115e4d489179d3f029e765211b2ad527ba59
 F src/test_thread.c e297dd41db0b249646e69f97d36ec13e56e8b730
 F src/tokenize.c a96abe15a8db6fea2e964cdce2acba9ed17bc26f
 F src/trigger.c 9bd3b6fa0beff4a02d262c96466f752ec15a7fc3
-F src/update.c 6d5f7728ec254c4a36a06a744f45b232b2eef857
+F src/update.c d6f214aad7eab5aaec5f966058b0828b3f7d6706
 F src/utf.c 8c94fa10efc78c2568d08d436acc59df4df7191b
 F src/util.c 02c57c302ef738ff5b554953c12d8f919e501583
 F src/vacuum.c 3524411bfb58aac0d87eadd3e5b7cd532772af30
@@ -183,7 +183,7 @@ F src/vdbeblob.c cc713c142c3d4952b380c98ee035f850830ddbdb
 F src/vdbefifo.c a30c237b2a3577e1415fb6e288cbb6b8ed1e5736
 F src/vdbemem.c 095e18f84b3171a5f2d71fa93a4bfc64220c1cfe
 F src/vtab.c 00cd16317b29495c185ff40e4b227917d5a371b2
-F src/where.c 86b042dcd57f8428a75ddb59e6289eded6f6af09
+F src/where.c a686f1e04f1ce5515a801fb3f3a358ef2cbb6ed2
 F tclinstaller.tcl 4356d9d94d2b5ed5e68f9f0c80c4df3048dd7617
 F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
 F test/all.test d56a3ca8acdf761204aff0a2e7aa5eb8e11b31e6
@@ -522,7 +522,7 @@ F test/vacuum.test f67853a15caa120af591f819670f01a11fcc2bfc
 F test/vacuum2.test d3b9691541fe6ed5c711f547a1c7d70e9760ac6f
 F test/vacuum3.test 72fbc903b085cd5f8b3a513b23f8ce44f7e0b06f
 F test/varint.test ab7b110089a08b9926ed7390e7e97bdefeb74102
-F test/veryquick.test 9bba6886026bb58a7332b6c96fd8270469f02177
+F test/veryquick.test 93fd0500c367e6c03ea757071cfe4ca749533946
 F test/view.test 4864e3841ab3213a95297718b94d5d6a8d3bc78b
 F test/vtab1.test bd905d1d43637a700308da6ffcc4e014c27e2f0a
 F test/vtab2.test 1da49b015582965a8fc386aa23d051a5a622b08e
@@ -625,7 +625,7 @@ F www/tclsqlite.tcl 8be95ee6dba05eabcd27a9d91331c803f2ce2130
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P 80311594149af093f1719ec433a633c332a5955e
+P a2da7f9ac24ed17329ce9bde2e521a5b945e4ec2
-R 91477f9b363e3127fe8f0174bc0a918e
+R 7e441dc4d958d560f1e90cd3d12b42d2
 U drh
-Z a1e09e21b5d00d19682913f02726b0e4
+Z cff67db9b3badb72e8bf8a1dd2f2e574

manifest.uuid

@@ -1 +1 @@
-a2da7f9ac24ed17329ce9bde2e521a5b945e4ec2
+fba97f7874d723111e873d1470fc1a95e64f922d

src/select.c

@@ -12,7 +12,7 @@
 ** This file contains C code routines that are called by the parser
 ** to handle SELECT statements in SQLite.
 **
-** $Id: select.c,v 1.425 2008/04/01 05:07:15 drh Exp $
+** $Id: select.c,v 1.426 2008/04/10 13:33:18 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -2677,7 +2677,7 @@ static int flattenSubquery(
 
 /*
 ** Analyze the SELECT statement passed as an argument to see if it
-** is a min() or max() query. Return ORDERBY_MIN or ORDERBY_MAX if 
+** is a min() or max() query. Return WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX if 
 ** it is, or 0 otherwise. At present, a query is considered to be
 ** a min()/max() query if:
 **
@@ -2690,18 +2690,18 @@ static int minMaxQuery(Parse *pParse, Select *p){
   Expr *pExpr;
   ExprList *pEList = p->pEList;
 
-  if( pEList->nExpr!=1 ) return ORDERBY_NORMAL;
+  if( pEList->nExpr!=1 ) return WHERE_ORDERBY_NORMAL;
   pExpr = pEList->a[0].pExpr;
   pEList = pExpr->pList;
   if( pExpr->op!=TK_AGG_FUNCTION || pEList==0 || pEList->nExpr!=1 ) return 0;
-  if( pEList->a[0].pExpr->op!=TK_AGG_COLUMN ) return ORDERBY_NORMAL;
+  if( pEList->a[0].pExpr->op!=TK_AGG_COLUMN ) return WHERE_ORDERBY_NORMAL;
-  if( pExpr->token.n!=3 ) return ORDERBY_NORMAL;
+  if( pExpr->token.n!=3 ) return WHERE_ORDERBY_NORMAL;
   if( sqlite3StrNICmp((char*)pExpr->token.z,"min",3)==0 ){
-    return ORDERBY_MIN;
+    return WHERE_ORDERBY_MIN;
   }else if( sqlite3StrNICmp((char*)pExpr->token.z,"max",3)==0 ){
-    return ORDERBY_MAX;
+    return WHERE_ORDERBY_MAX;
   }
-  return ORDERBY_NORMAL;
+  return WHERE_ORDERBY_NORMAL;
 }
 
 /*
@@ -3559,7 +3559,7 @@ int sqlite3Select(
       if( flag ){
         pDel = pMinMax = sqlite3ExprListDup(db, p->pEList->a[0].pExpr->pList);
         if( pMinMax && !db->mallocFailed ){
-          pMinMax->a[0].sortOrder = ((flag==ORDERBY_MIN)?0:1);
+          pMinMax->a[0].sortOrder = ((flag==WHERE_ORDERBY_MIN)?0:1);
           pMinMax->a[0].pExpr->op = TK_COLUMN;
         }
       }
@@ -3577,7 +3577,7 @@ int sqlite3Select(
       updateAccumulator(pParse, &sAggInfo);
       if( !pMinMax && flag ){
         sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
-        VdbeComment((v, "%s() by index", (flag==ORDERBY_MIN?"min":"max")));
+        VdbeComment((v, "%s() by index", (flag==WHERE_ORDERBY_MIN?"min":"max")));
       }
       sqlite3WhereEnd(pWInfo);
       finalizeAggFunctions(pParse, &sAggInfo);

src/sqliteInt.h

@@ -11,7 +11,7 @@
 *************************************************************************
 ** Internal interface definitions for SQLite.
 **
-** @(#) $Id: sqliteInt.h,v 1.689 2008/04/05 18:41:43 drh Exp $
+** @(#) $Id: sqliteInt.h,v 1.690 2008/04/10 13:33:18 drh Exp $
 */
 #ifndef _SQLITEINT_H_
 #define _SQLITEINT_H_
@@ -1311,9 +1311,13 @@ struct WhereLevel {
   sqlite3_index_info *pIdxInfo;  /* Index info for n-th source table */
 };
 
-#define ORDERBY_NORMAL 0
+/*
-#define ORDERBY_MIN    1
+** Flags appropriate for the wflags parameter of sqlite3WhereBegin().
-#define ORDERBY_MAX    2
+*/
+#define WHERE_ORDERBY_NORMAL     0   /* No-op */
+#define WHERE_ORDERBY_MIN        1   /* ORDER BY processing for min() func */
+#define WHERE_ORDERBY_MAX        2   /* ORDER BY processing for max() func */
+#define WHERE_ONEPASS_DESIRED    4   /* Want to do one-pass UPDATE/DELETE */
 
 /*
 ** The WHERE clause processing routine has two halves.  The
@@ -1323,7 +1327,8 @@ struct WhereLevel {
 ** into the second half to give some continuity.
 */
 struct WhereInfo {
-  Parse *pParse;
+  Parse *pParse;       /* Parsing and code generating context */
+  u8 okOnePass;        /* Ok to use one-pass algorithm for UPDATE or DELETE */
   SrcList *pTabList;   /* List of tables in the join */
   int iTop;            /* The very beginning of the WHERE loop */
   int iContinue;       /* Jump here to continue with next record */

src/update.c

@@ -12,7 +12,7 @@
 ** This file contains C code routines that are called by the parser
 ** to handle UPDATE statements.
 **
-** $Id: update.c,v 1.175 2008/04/01 05:07:15 drh Exp $
+** $Id: update.c,v 1.176 2008/04/10 13:33:18 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -103,6 +103,7 @@ void sqlite3Update(
   NameContext sNC;       /* The name-context to resolve expressions in */
   int iDb;               /* Database containing the table being updated */
   int j1;                /* Addresses of jump instructions */
+  int okOnePass;         /* True for one-pass algorithm without the FIFO */
 
 #ifndef SQLITE_OMIT_TRIGGER
   int isView;                  /* Trying to update a view */
@@ -341,13 +342,16 @@ void sqlite3Update(
 
   /* Begin the database scan
   */
-  pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0);
+  sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid);
+  pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0,
+                             WHERE_ONEPASS_DESIRED);
   if( pWInfo==0 ) goto update_cleanup;
+  okOnePass = pWInfo->okOnePass;
 
   /* Remember the rowid of every item to be updated.
   */
-  sqlite3VdbeAddOp2(v, IsVirtual(pTab) ? OP_VRowid : OP_Rowid,iCur,regOldRowid);
+  sqlite3VdbeAddOp2(v, IsVirtual(pTab)?OP_VRowid:OP_Rowid, iCur, regOldRowid);
-  sqlite3VdbeAddOp2(v, OP_FifoWrite, regOldRowid, 0);
+  if( !okOnePass ) sqlite3VdbeAddOp2(v, OP_FifoWrite, regOldRowid, 0);
 
   /* End the database scan loop.
   */
@@ -367,7 +371,7 @@ void sqlite3Update(
     ** action, then we need to open all indices because we might need
     ** to be deleting some records.
     */
-    sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite); 
+    if( !okOnePass ) sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite); 
     if( onError==OE_Replace ){
       openAll = 1;
     }else{
@@ -395,7 +399,13 @@ void sqlite3Update(
   }
 
   /* Top of the update loop */
+  if( okOnePass ){
+    int a1 = sqlite3VdbeAddOp1(v, OP_NotNull, regOldRowid);
+    addr = sqlite3VdbeAddOp0(v, OP_Goto);
+    sqlite3VdbeJumpHere(v, a1);
+  }else{
     addr = sqlite3VdbeAddOp2(v, OP_FifoRead, regOldRowid, 0);
+  }
 
   if( triggers_exist ){
     int regRowid;

src/where.c

@@ -16,7 +16,7 @@
 ** so is applicable.  Because this module is responsible for selecting
 ** indices, you might also think of this module as the "query optimizer".
 **
-** $Id: where.c,v 1.297 2008/04/01 05:07:15 drh Exp $
+** $Id: where.c,v 1.298 2008/04/10 13:33:18 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -2002,7 +2002,7 @@ WhereInfo *sqlite3WhereBegin(
   SrcList *pTabList,    /* A list of all tables to be scanned */
   Expr *pWhere,         /* The WHERE clause */
   ExprList **ppOrderBy, /* An ORDER BY clause, or NULL */
-  u8 obflag             /* One of ORDERBY_MIN, ORDERBY_MAX or ORDERBY_NORMAL */
+  u8 wflags             /* One of the WHERE_* flags defined in sqliteInt.h */
 ){
   int i;                     /* Loop counter */
   WhereInfo *pWInfo;         /* Will become the return value of this function */
@@ -2210,6 +2210,17 @@ WhereInfo *sqlite3WhereBegin(
     *ppOrderBy = 0;
   }
 
+  /* If the caller is an UPDATE or DELETE statement that is requesting
+  ** to use a one-pass algorithm, determine if this is appropriate.
+  ** The one-pass algorithm only works if the WHERE clause constraints
+  ** the statement to update a single row.
+  */
+  assert( (wflags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
+  if( (wflags & WHERE_ONEPASS_DESIRED)!=0 && (andFlags & WHERE_UNIQUE)!=0 ){
+    pWInfo->okOnePass = 1;
+    pWInfo->a[0].flags &= ~WHERE_IDX_ONLY;
+  }
+
   /* Open all tables in the pTabList and any indices selected for
   ** searching those tables.
   */
@@ -2258,8 +2269,9 @@ WhereInfo *sqlite3WhereBegin(
     }else
 #endif
     if( (pLevel->flags & WHERE_IDX_ONLY)==0 ){
-      sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, OP_OpenRead);
+      int op = pWInfo->okOnePass ? OP_OpenWrite : OP_OpenRead;
-      if( pTab->nCol<(sizeof(Bitmask)*8) ){
+      sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, op);
+      if( !pWInfo->okOnePass && pTab->nCol<(sizeof(Bitmask)*8) ){
         Bitmask b = pTabItem->colUsed;
         int n = 0;
         for(; b; b=b>>1, n++){}
@@ -2496,7 +2508,7 @@ WhereInfo *sqlite3WhereBegin(
       ** the first one after the nEq equality constraints in the index,
       ** this requires some special handling.
       */
-      if( (obflag==ORDERBY_MIN)
+      if( (wflags&WHERE_ORDERBY_MIN)!=0
        && (pLevel->flags&WHERE_ORDERBY)
        && (pIdx->nColumn>nEq)
        && (pOrderBy->a[0].pExpr->iColumn==pIdx->aiColumn[nEq])
@@ -2635,7 +2647,7 @@ WhereInfo *sqlite3WhereBegin(
       regBase = codeAllEqualityTerms(pParse, pLevel, &wc, notReady, 1);
       nxt = pLevel->nxt;
 
-      if( (obflag==ORDERBY_MIN)
+      if( (wflags&WHERE_ORDERBY_MIN)!=0
        && (pLevel->flags&WHERE_ORDERBY) 
        && (pIdx->nColumn>nEq)
        && (pOrderBy->a[0].pExpr->iColumn==pIdx->aiColumn[nEq])
@@ -2853,7 +2865,7 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
     Table *pTab = pTabItem->pTab;
     assert( pTab!=0 );
     if( pTab->isEphem || pTab->pSelect ) continue;
-    if( (pLevel->flags & WHERE_IDX_ONLY)==0 ){
+    if( !pWInfo->okOnePass && (pLevel->flags & WHERE_IDX_ONLY)==0 ){
       sqlite3VdbeAddOp1(v, OP_Close, pTabItem->iCursor);
     }
     if( pLevel->pIdx!=0 ){

test/veryquick.test

@@ -6,7 +6,7 @@
 #***********************************************************************
 # This file runs all tests.
 #
-# $Id: veryquick.test,v 1.1 2008/03/31 23:51:35 drh Exp $
+# $Id: veryquick.test,v 1.2 2008/04/10 13:33:18 drh Exp $
 
 proc lshift {lvar} {
   upvar $lvar l
@@ -95,6 +95,7 @@ set EXCLUDE {
   speed4.test
   speed4p.test
   sqllimits1.test
+  vacuum3.test
 
   tkt2686.test
   thread001.test