Better handle WHERE terms that are common to two or more OR branches when planning virtual table queries.

FossilOrigin-Name: 1976c3f7e1fe77cf3367710e8ada230a3672ed374e316425164e42b2622526c7

ext/fts5/fts5_main.c

@@ -533,10 +533,10 @@ static int fts5UsePatternMatch(
 ** This function ensures that there is at most one "r" or "=". And that if
 ** there exists an "=" then there is no "<" or ">".
 **
-** Costs are assigned as follows:
+** If an unusable MATCH operator is present in the WHERE clause, then
+** SQLITE_CONSTRAINT is returned.
 **
-**  a) If an unusable MATCH operator is present in the WHERE clause, the
+** Costs are assigned as follows:
-**     cost is unconditionally set to 1e50 (a really big number).
 **
 **  a) If a MATCH operator is present, the cost depends on the other
 **     constraints also present. As follows:
@@ -569,7 +569,7 @@ static int fts5BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
   int bSeenEq = 0;
   int bSeenGt = 0;
   int bSeenLt = 0;
-  int bSeenMatch = 0;
+  int nSeenMatch = 0;
   int bSeenRank = 0;
 
 
@@ -600,18 +600,15 @@ static int fts5BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
       /* A MATCH operator or equivalent */
       if( p->usable==0 || iCol<0 ){
         /* As there exists an unusable MATCH constraint this is an 
-        ** unusable plan. Set a prohibitively high cost. */
+        ** unusable plan. Return SQLITE_CONSTRAINT. */
-        pInfo->estimatedCost = 1e50;
+        return SQLITE_CONSTRAINT;
-        assert( iIdxStr < pInfo->nConstraint*6 + 1 );
-        idxStr[iIdxStr] = 0;
-        return SQLITE_OK;
       }else{
         if( iCol==nCol+1 ){
           if( bSeenRank ) continue;
           idxStr[iIdxStr++] = 'r';
           bSeenRank = 1;
         }else if( iCol>=0 ){
-          bSeenMatch = 1;
+          nSeenMatch++;
           idxStr[iIdxStr++] = 'M';
           sqlite3_snprintf(6, &idxStr[iIdxStr], "%d", iCol);
           idxStr += strlen(&idxStr[iIdxStr]);
@@ -628,7 +625,7 @@ static int fts5BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
         idxStr += strlen(&idxStr[iIdxStr]);
         pInfo->aConstraintUsage[i].argvIndex = ++iCons;
         assert( idxStr[iIdxStr]=='\0' );
-        bSeenMatch = 1;
+        nSeenMatch++;
       }else if( bSeenEq==0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ && iCol<0 ){
         idxStr[iIdxStr++] = '=';
         bSeenEq = 1;
@@ -665,7 +662,7 @@ static int fts5BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
   */
   if( pInfo->nOrderBy==1 ){
     int iSort = pInfo->aOrderBy[0].iColumn;
-    if( iSort==(pConfig->nCol+1) && bSeenMatch ){
+    if( iSort==(pConfig->nCol+1) && nSeenMatch>0 ){
       idxFlags |= FTS5_BI_ORDER_RANK;
     }else if( iSort==-1 && (!pInfo->aOrderBy[0].desc || !pConfig->bTokendata) ){
       idxFlags |= FTS5_BI_ORDER_ROWID;
@@ -680,14 +677,17 @@ static int fts5BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
 
   /* Calculate the estimated cost based on the flags set in idxFlags. */
   if( bSeenEq ){
-    pInfo->estimatedCost = bSeenMatch ? 100.0 : 10.0;
+    pInfo->estimatedCost = nSeenMatch ? 1000.0 : 10.0;
-    if( bSeenMatch==0 ) fts5SetUniqueFlag(pInfo);
+    if( nSeenMatch==0 ) fts5SetUniqueFlag(pInfo);
   }else if( bSeenLt && bSeenGt ){
-    pInfo->estimatedCost = bSeenMatch ? 500.0 : 250000.0;
+    pInfo->estimatedCost = nSeenMatch ? 5000.0 : 250000.0;
   }else if( bSeenLt || bSeenGt ){
-    pInfo->estimatedCost = bSeenMatch ? 750.0 : 750000.0;
+    pInfo->estimatedCost = nSeenMatch ? 7500.0 : 750000.0;
   }else{
-    pInfo->estimatedCost = bSeenMatch ? 1000.0 : 1000000.0;
+    pInfo->estimatedCost = nSeenMatch ? 10000.0 : 1000000.0;
+  }
+  for(i=1; i<nSeenMatch; i++){
+    pInfo->estimatedCost *= 0.4;
   }
 
   pInfo->idxNum = idxFlags;

ext/fts5/test/fts5colset.test

@@ -79,7 +79,7 @@ foreach_detail_mode $::testprefix {
 
   do_catchsql_test 4.1 {
     SELECT * FROM t1 WHERE rowid MATCH 'a'
-  } {1 {unable to use function MATCH in the requested context}}
+  } {1 {no query solution}}
 }
 
 #-------------------------------------------------------------------------

ext/fts5/test/fts5misc.test

@@ -535,5 +535,36 @@ do_execsql_test 19.0 {
   COMMIT;
 }
 
+#-------------------------------------------------------------------------
+reset_db
+do_execsql_test 20.0 {
+  CREATE VIRTUAL TABLE x1 USING fts5(a);
+  INSERT INTO x1(rowid, a) VALUES
+      (1, 'a b c d'),
+      (2, 'x b c d'),
+      (3, 'x y z d'),
+      (4, 'a y c x');
+}
+
+do_execsql_test 20.1 {
+  SELECT rowid FROM x1 WHERE x1 MATCH 'a' AND x1 MATCH 'b';
+} {1}
+
+do_execsql_test 20.2 {
+  SELECT rowid FROM x1 WHERE x1 MATCH 'a' AND x1 MATCH 'y';
+} {4}
+
+do_execsql_test 20.3 {
+  SELECT rowid FROM x1 WHERE x1 MATCH 'a' OR x1 MATCH 'y';
+} {1 4 3}
+
+do_execsql_test 20.4 {
+  SELECT rowid FROM x1 WHERE x1 MATCH 'a' OR (x1 MATCH 'y' AND x1 MATCH 'd');
+} {1 4 3}
+
+do_execsql_test 20.5 {
+  SELECT rowid FROM x1 WHERE x1 MATCH 'z' OR (x1 MATCH 'a' AND x1 MATCH 'd');
+} {3 1}
+
 finish_test
 

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\scouple\sof\smemory\sleaks\sin\sthe\sshell\stool\scode\sthat\scould\soccur\swhen\sprocessing\serrors.
+C Better\shandle\sWHERE\sterms\sthat\sare\scommon\sto\stwo\sor\smore\sOR\sbranches\swhen\splanning\svirtual\stable\squeries.
-D 2024-06-04T15:07:38.217
+D 2024-06-04T17:26:15.006
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -100,7 +100,7 @@ F ext/fts5/fts5_config.c 1ae512e7374caca6ab250055b3b29e46b007a27b098eafcc7ff4d13
 F ext/fts5/fts5_expr.c 85789f6fb01995f2578b60a360057ed754335a890b1ab2e57e238b3670a9ae6c
 F ext/fts5/fts5_hash.c adda4272be401566a6e0ba1acbe70ee5cb97fce944bc2e04dc707152a0ec91b1
 F ext/fts5/fts5_index.c ee0f4d50bc0c58a7c5ef7d645e7e38e1e59315b8ea9d722ae00c5f949ee65379
-F ext/fts5/fts5_main.c ac3aaf0c885cf4e274c0c09ece632e17ff2fce01f2c9c0f4c50ffbbb3e267bde
+F ext/fts5/fts5_main.c b1538b39182be8f2b6b1807c1ad426e0e5710e3ee2dcaeb7d0ae2b751103c237
 F ext/fts5/fts5_storage.c f9e31b0d155e9b2c92d5d3a09ad7a56b937fbf1c7f962e10f4ca6281349f3934
 F ext/fts5/fts5_tcl.c fdf7e2bb9a9186cfcaf2d2ce11d338309342b7a7593c2812bc54455db53da5d2
 F ext/fts5/fts5_test_mi.c 08c11ec968148d4cb4119d96d819f8c1f329812c568bac3684f5464be177d3ee
@@ -133,7 +133,7 @@ F ext/fts5/test/fts5bigpl.test 6466c89b38439f0aba26ac09e232a6b963f29b1cbe1304f6a
 F ext/fts5/test/fts5bigtok.test 541119e616c637caea925a8c028c37c2c29e94383e00aa2f9198d530724b6e36
 F ext/fts5/test/fts5cat.test daba0b80659460b0cb60bd1f40b402478a761fe7ea414c3c94c2be25568cc33a
 F ext/fts5/test/fts5circref.test f880dfd0d99f6fb73b88ccacb0927d18e833672fd906cc47d6b4e529419eaa62
-F ext/fts5/test/fts5colset.test 7031ce84fb4d312df5a99fc4e7b324e660ccb513c97eccdef469bfd52d3d0f8f
+F ext/fts5/test/fts5colset.test 544f4998cdbfe06a3123887fc0221612e8aa8192cdaff152872f1aadb10e6897
 F ext/fts5/test/fts5columnsize.test 45459ce4dd9fd853b6044cdc9674921bff89e3d840f348ca8c1630f9edbf5482
 F ext/fts5/test/fts5config.test 60094712debc59286c59aef0e6cf511c37d866802776a825ce437d26afe0817f
 F ext/fts5/test/fts5conflict.test bf6030a77dbb1bedfcc42e589ed7980846c995765d77460551e448b56d741244
@@ -186,7 +186,7 @@ F ext/fts5/test/fts5limits.test 8ab67cf5d311c124b6ceb0062d0297767176df4572d955fc
 F ext/fts5/test/fts5matchinfo.test 10c9a6f7fe61fb132299c4183c012770b10c4d5c2f2edb6df0b6607f683d737a
 F ext/fts5/test/fts5merge.test e92a8db28b45931e7a9c7b1bbd36101692759d00274df74d83fd29d25d53b3a6
 F ext/fts5/test/fts5merge2.test 3ebad1a59d6ad3fb66eff6523a09e95dc6367cbefb3cd73196801dea0425c8e2
-F ext/fts5/test/fts5misc.test 89dc46e37951b7f6653809f4abf6b1ca2f1fa62259efaf719339288f76fb6be9
+F ext/fts5/test/fts5misc.test b88aa28ff20238b394495b0795cddca1a62b98fa09b99e462a8abc572d04ee88
 F ext/fts5/test/fts5multi.test a15bc91cdb717492e6e1b66fec1c356cb57386b980c7ba5af1915f97fe878581
 F ext/fts5/test/fts5multiclient.test 5ff811c028d6108045ffef737f1e9f05028af2458e456c0937c1d1b8dea56d45
 F ext/fts5/test/fts5near.test 211477940142d733ac04fad97cb24095513ab2507073a99c2765c3ddd2ef58bd
@@ -776,7 +776,7 @@ F src/test9.c 12e5ba554d2d1cbe0158f6ab3f7ffcd7a86ee4e5
 F src/test_async.c 195ab49da082053fdb0f949c114b806a49ca770a
 F src/test_autoext.c 915d245e736652a219a907909bb6710f0d587871
 F src/test_backup.c bf5da90c9926df0a4b941f2d92825a01bbe090a0
-F src/test_bestindex.c 770429c434221afe6216ec81fe4c00ad3bbdad1d5e64576aa613ffb7c5a984f0
+F src/test_bestindex.c 1b5a1407b66c5caa67cfe1d93d96de5ec5d9d516bc69eb512482f85c037858c3
 F src/test_blob.c ae4a0620b478548afb67963095a7417cd06a4ec0a56adb453542203bfdcb31ce
 F src/test_btree.c 8b2dc8b8848cf3a4db93f11578f075e82252a274
 F src/test_config.c 5fa77ee6064ba546e144c4fea870c5ede2c54314616f81485c6a9c4192100c75
@@ -840,7 +840,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 887fc4ca3f020ebb2e376f222069570834ac63bf50111ef0cbf3ae417048ed89
 F src/wal.h ba252daaa94f889f4b2c17c027e823d9be47ce39da1d3799886bbd51f0490452
 F src/walker.c 7c7ea0115345851c3da4e04e2e239a29983b61fb5b038b94eede6aba462640e2
-F src/where.c 593d28d3776985733da0f09639100003b444a43db7b6f9a35139f544fdbea358
+F src/where.c 343e74d65856665f2aac59a9fcefecfc988e9af4aafa0bd1b8332a89c6c725b4
 F src/whereInt.h 002adc3aa2cc10733b9b27958fdbe893987cd989fab25a9853941c1f9b9b0a65
 F src/wherecode.c 5ad509221ebb4d3b35a8a6ef361f2c5b54129b8c273aa434dd3053d2e25d1794
 F src/whereexpr.c 67d15caf88a1a9528283d68ff578e024cf9fe810b517bb0343e5aaf695ad97dd
@@ -940,7 +940,7 @@ F test/bestindex8.test b63a4f171a2c83d481bb14c431a8b72e85d27b2ffdaa0435a95d58ca9
 F test/bestindex9.test 1a4b93db117fd8abe74ae9be982f86aa72f01e60cd4ac541e6ede39673a451a0
 F test/bestindexA.test e1b5def6b190797cacf008e6815ffb78fb30261999030d60a728d572eef44c7f
 F test/bestindexB.test 328b97b69cd1a20928d5997f9ecb04d2e00f1d18e19ab27f9e9adb44d7bc51ce
-F test/bestindexC.test 9e6f184be080fd9c4605a7e5c7097eed1a259372f9af78151c37b072a9086f86
+F test/bestindexC.test 2df6ada16d8f00d9bb6a9664d9c323560aeed0e0ebc7a32b99d85d70037fd250
 F test/between.test b9a65fb065391980119e8a781a7409d3fcf059d89968279c750e190a9a1d5263
 F test/bigfile.test aa74f4e5db51c8e54a1d9de9fa65d01d1eb20b59
 F test/bigfile2.test 1b489a3a39ae90c7f027b79110d6b4e1dbc71bfc
@@ -2194,8 +2194,9 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P afa45c4f5afc9248ca4a1e775404a460280bb9a58a92eae508ae00fb2f675dc6
+P e84f09d469ee76a5b5e44baf6a69b90c69d4160fa4c32de04a96f868643acd96 85dcd0a8479a658203833cfd75f22813faa26d4793ebfbb8843035d683bee105
-R 332c194faf67e4e5d499e21ef0877039
+R ef252a4e30665afc837737e2dd6e6acf
+T +closed 85dcd0a8479a658203833cfd75f22813faa26d4793ebfbb8843035d683bee105
 U dan
-Z 25f8afeca77d9ed28a678ff29d2afdb8
+Z 63031e840e155842bdee98d1a8498c9b
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-e84f09d469ee76a5b5e44baf6a69b90c69d4160fa4c32de04a96f868643acd96
+1976c3f7e1fe77cf3367710e8ada230a3672ed374e316425164e42b2622526c7

src/test_bestindex.c

@@ -305,11 +305,9 @@ static int tclFilter(
   Tcl_IncrRefCount(pScript);
   Tcl_ListObjAppendElement(interp, pScript, Tcl_NewStringObj("xFilter", -1));
   Tcl_ListObjAppendElement(interp, pScript, Tcl_NewIntObj(idxNum));
-  if( idxStr ){
+  Tcl_ListObjAppendElement(
-    Tcl_ListObjAppendElement(interp, pScript, Tcl_NewStringObj(idxStr, -1));
+      interp, pScript, Tcl_NewStringObj(idxStr ? idxStr : "", -1)
-  }else{
+  );
-    Tcl_ListObjAppendElement(interp, pScript, Tcl_NewStringObj("", -1));
-  }
 
   pArg = Tcl_NewObj();
   Tcl_IncrRefCount(pArg);
@@ -530,6 +528,7 @@ static int SQLITE_TCLAPI testBestIndexObj(
     "distinct",                   /* 3 */
     "in",                         /* 4 */
     "rhs_value",                  /* 5 */
+    "collation",                  /* 6 */
     0
   };
   int ii;
@@ -610,6 +609,17 @@ static int SQLITE_TCLAPI testBestIndexObj(
       Tcl_SetObjResult(interp, Tcl_NewStringObj(zVal, -1));
       break;
     }
+
+    case 6: assert( sqlite3_stricmp(azSub[ii], "collation")==0 ); {
+      int iCons = 0;
+      const char *zColl = "";
+      if( Tcl_GetIntFromObj(interp, objv[2], &iCons) ){
+        return TCL_ERROR;
+      }
+      zColl = sqlite3_vtab_collation(pIdxInfo, iCons);
+      Tcl_SetObjResult(interp, Tcl_NewStringObj(zColl, -1));
+      break;
+    }
   }
 
   return TCL_OK;
@@ -700,6 +710,10 @@ static int tclBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
               pIdxInfo->aConstraintUsage[iCons].omit = bOmit;
             }
           }
+        }else
+        if( sqlite3_stricmp("constraint", zCmd)==0 ){
+          rc = SQLITE_CONSTRAINT;
+          pTab->base.zErrMsg = sqlite3_mprintf("%s", Tcl_GetString(p));
         }else{
           rc = SQLITE_ERROR;
           pTab->base.zErrMsg = sqlite3_mprintf("unexpected: %s", zCmd);

src/where.c

@@ -1346,6 +1346,20 @@ static SQLITE_NOINLINE void sqlite3ConstructBloomFilter(
 
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Return term iTerm of the WhereClause passed as the first argument. Terms
+** are numbered from 0 upwards, starting with the terms in pWC->a[], then
+** those in pWC->pOuter->a[] (if any), and so on.
+*/
+static WhereTerm *termFromWhereClause(WhereClause *pWC, int iTerm){
+  WhereClause *p;
+  for(p=pWC; p; p=p->pOuter){
+    if( iTerm<p->nTerm ) return &p->a[iTerm];
+    iTerm -= p->nTerm;
+  }
+  return 0;
+}
+
 /*
 ** Allocate and populate an sqlite3_index_info structure. It is the
 ** responsibility of the caller to eventually release the structure
@@ -1372,6 +1386,7 @@ static sqlite3_index_info *allocateIndexInfo(
   const Table *pTab;
   int eDistinct = 0;
   ExprList *pOrderBy = pWInfo->pOrderBy;
+  WhereClause *p;
 
   assert( pSrc!=0 );
   pTab = pSrc->pTab;
@@ -1382,28 +1397,30 @@ static sqlite3_index_info *allocateIndexInfo(
   ** Mark each term with the TERM_OK flag.  Set nTerm to the number of
   ** terms found.
   */
-  for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
+  for(p=pWC, nTerm=0; p; p=p->pOuter){
-    pTerm->wtFlags &= ~TERM_OK;
+    for(i=0, pTerm=p->a; i<p->nTerm; i++, pTerm++){
-    if( pTerm->leftCursor != pSrc->iCursor ) continue;
+      pTerm->wtFlags &= ~TERM_OK;
-    if( pTerm->prereqRight & mUnusable ) continue;
+      if( pTerm->leftCursor != pSrc->iCursor ) continue;
-    assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) );
+      if( pTerm->prereqRight & mUnusable ) continue;
-    testcase( pTerm->eOperator & WO_IN );
+      assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) );
-    testcase( pTerm->eOperator & WO_ISNULL );
+      testcase( pTerm->eOperator & WO_IN );
-    testcase( pTerm->eOperator & WO_IS );
+      testcase( pTerm->eOperator & WO_ISNULL );
-    testcase( pTerm->eOperator & WO_ALL );
+      testcase( pTerm->eOperator & WO_IS );
-    if( (pTerm->eOperator & ~(WO_EQUIV))==0 ) continue;
+      testcase( pTerm->eOperator & WO_ALL );
-    if( pTerm->wtFlags & TERM_VNULL ) continue;
+      if( (pTerm->eOperator & ~(WO_EQUIV))==0 ) continue;
+      if( pTerm->wtFlags & TERM_VNULL ) continue;
 
-    assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
-    assert( pTerm->u.x.leftColumn>=XN_ROWID );
+      assert( pTerm->u.x.leftColumn>=XN_ROWID );
-    assert( pTerm->u.x.leftColumn<pTab->nCol );
+      assert( pTerm->u.x.leftColumn<pTab->nCol );
-    if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0
+      if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0
-     && !constraintCompatibleWithOuterJoin(pTerm,pSrc)
+          && !constraintCompatibleWithOuterJoin(pTerm,pSrc)
-    ){
+        ){
-      continue;
+        continue;
+      }
+      nTerm++;
+      pTerm->wtFlags |= TERM_OK;
     }
-    nTerm++;
-    pTerm->wtFlags |= TERM_OK;
   }
 
   /* If the ORDER BY clause contains only columns in the current
@@ -1482,49 +1499,52 @@ static sqlite3_index_info *allocateIndexInfo(
   pHidden->pParse = pParse;
   pHidden->eDistinct = eDistinct;
   pHidden->mIn = 0;
-  for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
+  for(p=pWC, i=j=0; p; p=p->pOuter){
-    u16 op;
+    int nLast = i+p->nTerm;;
-    if( (pTerm->wtFlags & TERM_OK)==0 ) continue;
+    for(pTerm=p->a; i<nLast; i++, pTerm++){
-    pIdxCons[j].iColumn = pTerm->u.x.leftColumn;
+      u16 op;
-    pIdxCons[j].iTermOffset = i;
+      if( (pTerm->wtFlags & TERM_OK)==0 ) continue;
-    op = pTerm->eOperator & WO_ALL;
+      pIdxCons[j].iColumn = pTerm->u.x.leftColumn;
-    if( op==WO_IN ){
+      pIdxCons[j].iTermOffset = i;
-      if( (pTerm->wtFlags & TERM_SLICE)==0 ){
+      op = pTerm->eOperator & WO_ALL;
-        pHidden->mIn |= SMASKBIT32(j);
+      if( op==WO_IN ){
+        if( (pTerm->wtFlags & TERM_SLICE)==0 ){
+          pHidden->mIn |= SMASKBIT32(j);
+        }
+        op = WO_EQ;
       }
-      op = WO_EQ;
+      if( op==WO_AUX ){
-    }
+        pIdxCons[j].op = pTerm->eMatchOp;
-    if( op==WO_AUX ){
+      }else if( op & (WO_ISNULL|WO_IS) ){
-      pIdxCons[j].op = pTerm->eMatchOp;
+        if( op==WO_ISNULL ){
-    }else if( op & (WO_ISNULL|WO_IS) ){
+          pIdxCons[j].op = SQLITE_INDEX_CONSTRAINT_ISNULL;
-      if( op==WO_ISNULL ){
+        }else{
-        pIdxCons[j].op = SQLITE_INDEX_CONSTRAINT_ISNULL;
+          pIdxCons[j].op = SQLITE_INDEX_CONSTRAINT_IS;
+        }
       }else{
-        pIdxCons[j].op = SQLITE_INDEX_CONSTRAINT_IS;
+        pIdxCons[j].op = (u8)op;
-      }
+        /* The direct assignment in the previous line is possible only because
-    }else{
+        ** the WO_ and SQLITE_INDEX_CONSTRAINT_ codes are identical.  The
-      pIdxCons[j].op = (u8)op;
+        ** following asserts verify this fact. */
-      /* The direct assignment in the previous line is possible only because
+        assert( WO_EQ==SQLITE_INDEX_CONSTRAINT_EQ );
-      ** the WO_ and SQLITE_INDEX_CONSTRAINT_ codes are identical.  The
+        assert( WO_LT==SQLITE_INDEX_CONSTRAINT_LT );
-      ** following asserts verify this fact. */
+        assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE );
-      assert( WO_EQ==SQLITE_INDEX_CONSTRAINT_EQ );
+        assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT );
-      assert( WO_LT==SQLITE_INDEX_CONSTRAINT_LT );
+        assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE );
-      assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE );
+        assert( pTerm->eOperator&(WO_IN|WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_AUX) );
-      assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT );
-      assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE );
-      assert( pTerm->eOperator&(WO_IN|WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_AUX) );
 
-      if( op & (WO_LT|WO_LE|WO_GT|WO_GE)
+        if( op & (WO_LT|WO_LE|WO_GT|WO_GE)
-       && sqlite3ExprIsVector(pTerm->pExpr->pRight)
+            && sqlite3ExprIsVector(pTerm->pExpr->pRight)
-      ){
+          ){
-        testcase( j!=i );
+          testcase( j!=i );
-        if( j<16 ) mNoOmit |= (1 << j);
+          if( j<16 ) mNoOmit |= (1 << j);
-        if( op==WO_LT ) pIdxCons[j].op = WO_LE;
+          if( op==WO_LT ) pIdxCons[j].op = WO_LE;
-        if( op==WO_GT ) pIdxCons[j].op = WO_GE;
+          if( op==WO_GT ) pIdxCons[j].op = WO_GE;
+        }
       }
+
+      j++;
     }
-
-    j++;
   }
   assert( j==nTerm );
   pIdxInfo->nConstraint = j;
@@ -1544,6 +1564,17 @@ static sqlite3_index_info *allocateIndexInfo(
   return pIdxInfo;
 }
 
+/*
+** Free and zero the sqlite3_index_info.idxStr value if needed.
+*/
+static void freeIdxStr(sqlite3_index_info *pIdxInfo){
+  if( pIdxInfo->needToFreeIdxStr ){
+    sqlite3_free(pIdxInfo->idxStr);
+    pIdxInfo->idxStr = 0;
+    pIdxInfo->needToFreeIdxStr = 0;
+  }
+}  
+
 /*
 ** Free an sqlite3_index_info structure allocated by allocateIndexInfo()
 ** and possibly modified by xBestIndex methods.
@@ -1559,6 +1590,7 @@ static void freeIndexInfo(sqlite3 *db, sqlite3_index_info *pIdxInfo){
     sqlite3ValueFree(pHidden->aRhs[i]); /* IMP: R-14553-25174 */
     pHidden->aRhs[i] = 0;
   }
+  freeIdxStr(pIdxInfo);
   sqlite3DbFree(db, pIdxInfo);
 }
 
@@ -4159,7 +4191,7 @@ static int whereLoopAddVirtualOne(
   ** arguments mUsable and mExclude. */
   pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
   for(i=0; i<nConstraint; i++, pIdxCons++){
-    WhereTerm *pTerm = &pWC->a[pIdxCons->iTermOffset];
+    WhereTerm *pTerm = termFromWhereClause(pWC, pIdxCons->iTermOffset);
     pIdxCons->usable = 0;
     if( (pTerm->prereqRight & mUsable)==pTerm->prereqRight
      && (pTerm->eOperator & mExclude)==0
@@ -4190,6 +4222,7 @@ static int whereLoopAddVirtualOne(
       ** Make no entries in the loop table.
       */
       WHERETRACE(0xffffffff, ("  ^^^^--- non-viable plan rejected!\n"));
+      freeIdxStr(pIdxInfo);
       return SQLITE_OK;
     }
     return rc;
@@ -4207,18 +4240,17 @@ static int whereLoopAddVirtualOne(
       int j = pIdxCons->iTermOffset;
       if( iTerm>=nConstraint
        || j<0
-       || j>=pWC->nTerm
+       || (pTerm = termFromWhereClause(pWC, j))==0
        || pNew->aLTerm[iTerm]!=0
        || pIdxCons->usable==0
       ){
         sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pTab->zName);
-        testcase( pIdxInfo->needToFreeIdxStr );
+        freeIdxStr(pIdxInfo);
         return SQLITE_ERROR;
       }
       testcase( iTerm==nConstraint-1 );
       testcase( j==0 );
       testcase( j==pWC->nTerm-1 );
-      pTerm = &pWC->a[j];
       pNew->prereq |= pTerm->prereqRight;
       assert( iTerm<pNew->nLSlot );
       pNew->aLTerm[iTerm] = pTerm;
@@ -4263,11 +4295,7 @@ static int whereLoopAddVirtualOne(
         ** the plan cannot be used. In these cases set variable *pbRetryLimit
         ** to true to tell the caller to retry with LIMIT and OFFSET 
         ** disabled. */
-        if( pIdxInfo->needToFreeIdxStr ){
+        freeIdxStr(pIdxInfo);
-          sqlite3_free(pIdxInfo->idxStr);
-          pIdxInfo->idxStr = 0;
-          pIdxInfo->needToFreeIdxStr = 0;
-        }
         *pbRetryLimit = 1;
         return SQLITE_OK;
       }
@@ -4280,7 +4308,7 @@ static int whereLoopAddVirtualOne(
       /* The non-zero argvIdx values must be contiguous.  Raise an
       ** error if they are not */
       sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pTab->zName);
-      testcase( pIdxInfo->needToFreeIdxStr );
+      freeIdxStr(pIdxInfo);
       return SQLITE_ERROR;
     }
   }
@@ -4335,7 +4363,7 @@ const char *sqlite3_vtab_collation(sqlite3_index_info *pIdxInfo, int iCons){
   if( iCons>=0 && iCons<pIdxInfo->nConstraint ){
     CollSeq *pC = 0;
     int iTerm = pIdxInfo->aConstraint[iCons].iTermOffset;
-    Expr *pX = pHidden->pWC->a[iTerm].pExpr;
+    Expr *pX = termFromWhereClause(pHidden->pWC, iTerm)->pExpr;
     if( pX->pLeft ){
       pC = sqlite3ExprCompareCollSeq(pHidden->pParse, pX);
     }
@@ -4381,7 +4409,9 @@ int sqlite3_vtab_rhs_value(
     rc = SQLITE_MISUSE_BKPT; /* EV: R-30545-25046 */
   }else{
     if( pH->aRhs[iCons]==0 ){
-      WhereTerm *pTerm = &pH->pWC->a[pIdxInfo->aConstraint[iCons].iTermOffset];
+      WhereTerm *pTerm = termFromWhereClause(
+          pH->pWC, pIdxInfo->aConstraint[iCons].iTermOffset
+      );
       rc = sqlite3ValueFromExpr(
           pH->pParse->db, pTerm->pExpr->pRight, ENC(pH->pParse->db),
           SQLITE_AFF_BLOB, &pH->aRhs[iCons]
@@ -4537,9 +4567,8 @@ static int whereLoopAddVirtual(
       Bitmask mNext = ALLBITS;
       assert( mNext>0 );
       for(i=0; i<nConstraint; i++){
-        Bitmask mThis = (
+        int iTerm = p->aConstraint[i].iTermOffset;
-            pWC->a[p->aConstraint[i].iTermOffset].prereqRight & ~mPrereq
+        Bitmask mThis = termFromWhereClause(pWC, iTerm)->prereqRight & ~mPrereq;
-        );
         if( mThis>mPrev && mThis<mNext ) mNext = mThis;
       }
       mPrev = mNext;
@@ -4575,7 +4604,6 @@ static int whereLoopAddVirtual(
     }
   }
 
-  if( p->needToFreeIdxStr ) sqlite3_free(p->idxStr);
   freeIndexInfo(pParse->db, p);
   WHERETRACE(0x800, ("END %s.addVirtual(), rc=%d\n", pSrc->pTab->zName, rc));
   return rc;

test/bestindexC.test

@@ -210,4 +210,143 @@ do_catchsql_test 4.4 {
   CREATE VIRTUAL TABLE y1 USING tcl(vtab_command "CREATE TABLE x1(insert)");
 } {1 {declare_vtab: near "insert": syntax error}}
 
+#-------------------------------------------------------------------------
+reset_db
+register_tcl_module db
+
+proc quote {str} {
+  return "'[string map {' ''} $str]'"
+}
+
+proc vtab_command {lVal method args} {
+  switch -- $method {
+    xConnect {
+      return "CREATE TABLE t1(a, b, c, d)"
+    }
+
+    xBestIndex {
+      set hdl [lindex $args 0]
+      set clist [$hdl constraints]
+
+      set res [list]
+      set idx 0
+      set idxnum 0
+
+      set cols(0) a
+      set cols(1) b
+      set cols(2) c
+
+      set lCons [list]
+
+      foreach c $clist {
+        array set a $c
+        if {$a(usable)==0} continue
+
+        if {($a(op)=="eq" || $a(op)=="is") && [info exists cols($a(column))]} {
+          lappend res omit $idx
+          set coll [$hdl collation $idx]
+          lappend lCons "$cols($a(column)) = %[llength $lCons]% COLLATE $coll"
+
+          set idxnum [expr {$idx + (1 << $a(column))}]
+          catch { unset cols($a(column)) }
+        }
+
+        incr idx
+      }
+
+      if {[llength [array names cols]]>0} {
+        set missing [list]
+        for {set i 0} {$i < 3} {incr i} {
+          catch { lappend missing $cols($i) }
+        }
+        set msg "missing required constraints: [join $missing ,]"
+        return [list constraint $msg]
+      }
+
+      set idxstr [join $lCons " AND "]
+      return "cost 1000 rows 1000 idxnum $idxnum $res idxstr {$idxstr}"
+    }
+
+    xFilter {
+      foreach {idxnum idxstr lArg} $args {}
+      set i 0
+      set where $idxstr
+      foreach a $lArg {
+        set where [string map [list %$i% [quote $a]] $where]
+        incr i
+      }
+   #   puts $where
+      return [list sql "SELECT rowid, * FROM $lVal WHERE $where"]
+    }
+  }
+
+  return {}
+}
+
+do_execsql_test 5.1 {
+  CREATE VIRTUAL TABLE x1 USING tcl(vtab_command t1);
+  CREATE TABLE t1(a, b, c, d);
+}
+
+foreach {tn where ok} {
+  0    "WHERE a=? AND b=? AND c=? AND c=?"              1
+  1    "WHERE a=? AND b=? AND c=?"                      1
+  2    "WHERE a=? AND b=? AND (c=? OR c=?)"             1
+  3    "WHERE a=? AND b=? AND (c=? OR c=? OR c=?)"      1
+  4    "WHERE a=? AND b=? AND (c IS ? OR c IS ?)"       1
+  5    "WHERE a=? AND ((b=? AND c=?) OR (c=? AND b=?))" 1
+  6    "WHERE a=? AND ((b=? AND c=?) OR (c=?))"         0
+} {
+  do_test 5.2.$tn {
+    catch { execsql "SELECT * FROM x1 $::where" } msg
+#    if {$tn==0 || $tn==2 || $tn==3} { puts "MSG: $msg" }
+  } [expr !$ok]
+}
+
+do_execsql_test 5.3 {
+  SELECT * FROM x1 WHERE (a, b, c) = (?, ?, ?);
+}
+
+do_execsql_test 5.4 {
+  INSERT INTO t1(rowid, a, b, c, d) VALUES(1, 'x', 'y', 'z', 'one');
+  INSERT INTO t1(rowid, a, b, c, d) VALUES(2, 'X', 'Y', 'Z', 'two');
+  SELECT * FROM x1 WHERE (a, b, c) = ('X', 'Y', 'Z');
+} {X Y Z two}
+do_execsql_test 5.5 {
+  SELECT * FROM x1 WHERE a='x' AND b='y' AND c='z';
+} {x y z one}
+do_execsql_test 5.6 {
+  SELECT * FROM x1 
+  WHERE a='x' COLLATE nocase AND b='y' COLLATE nocase AND c='z'COLLATE nocase;
+} {x y z one X Y Z two}
+
+do_execsql_test 5.7 {
+  DELETE FROM t1;
+
+  INSERT INTO t1(rowid, a, b, c, d) VALUES(0, 'x', 'y', 'z', 'zero');
+  INSERT INTO t1(rowid, a, b, c, d) VALUES(1, 'x', 'y', 'Z', 'one');
+  INSERT INTO t1(rowid, a, b, c, d) VALUES(2, 'x', 'Y', 'z', 'two');
+  INSERT INTO t1(rowid, a, b, c, d) VALUES(3, 'x', 'Y', 'Z', 'three');
+  INSERT INTO t1(rowid, a, b, c, d) VALUES(4, 'X', 'y', 'z', 'four');
+  INSERT INTO t1(rowid, a, b, c, d) VALUES(5, 'X', 'y', 'Z', 'five');
+  INSERT INTO t1(rowid, a, b, c, d) VALUES(6, 'X', 'Y', 'z', 'six');
+  INSERT INTO t1(rowid, a, b, c, d) VALUES(7, 'X', 'Y', 'z', 'seven');
+}
+
+do_execsql_test 5.8 {
+  SELECT d FROM x1 
+  WHERE a='x' AND ((b='y' AND c='z') OR (b='Y' AND c='z' COLLATE nocase))
+} {
+  zero two three
+}
+
+do_execsql_test 5.9 {
+  SELECT d FROM x1 
+  WHERE a='x' COLLATE nocase 
+  AND ((b='y' AND c='z') OR (b='Y' AND c='z' COLLATE nocase))
+} {
+  zero four two
+  three six seven
+}
+
 finish_test