Avoid generating hints using constraints that are also used to initialize the

cursor, since presumably the cursor already knows about those constraints.

FossilOrigin-Name: 142b048ac778620dd4e448c2e969982eb8188501

manifest

@@ -1,5 +1,5 @@
-C Change\sthe\sdisplay\sof\sthe\sP4\soperand\sof\sCursorHint\sin\sEXPLAIN\soutput\sto\nfunction\snotation.
+C Avoid\sgenerating\shints\susing\sconstraints\sthat\sare\salso\sused\sto\sinitialize\sthe\ncursor,\ssince\spresumably\sthe\scursor\salready\sknows\sabout\sthose\sconstraints.
-D 2015-08-15T00:51:23.737
+D 2015-08-17T17:19:28.483
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 2fc9ca6bf5949d415801c007ed3004a4bdb7c380
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -414,7 +414,7 @@ F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
 F src/walker.c c253b95b4ee44b21c406e2a1052636c31ea27804
 F src/where.c ef95e56b6e7cdfa3ae0b6f72e3578391addfa965
 F src/whereInt.h 5f87e3c4b0551747d119730dfebddd3c54f04047
-F src/wherecode.c 16045545fb44878a7ba61db645521f30f9265893
+F src/wherecode.c 148c5dc225551309f489a5c44b8a0f7800c9794b
 F src/whereexpr.c 9ce1c9cfedbf80c93c7d899497025ec8256ce652
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/affinity2.test a6d901b436328bd67a79b41bb0ac2663918fe3bd
@@ -560,7 +560,7 @@ F test/crashtest1.c 09c1c7d728ccf4feb9e481671e29dda5669bbcc2
 F test/createtab.test b5de160630b209c4b8925bdcbbaf48cc90b67fe8
 F test/cse.test 277350a26264495e86b1785f34d2d0c8600e021c
 F test/ctime.test 7bd009071e242aac4f18521581536b652b789a47
-F test/cursorhint.test 0d79cce943e4e61910d9a5cf73b1e57b2b42429f
+F test/cursorhint.test b1f86e9c959231094d8fe214518667548083063e
 F test/date.test 42973251b9429f2c41b77eb98a7b0b0ba2d3b2c0
 F test/dbstatus.test 8de104bb5606f19537d23cd553b41349b5ab1204
 F test/dbstatus2.test 10418e62b3db5dca070f0c3eef3ea13946f339c2
@@ -1374,7 +1374,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 83a844357e132683ab3d88eee0fe32a8beeb6662
+P bee73d429cb0e99b43fb191ac15e298d0353b135
-R 64f1f656f75dd3e1a8b619dc73ce4cbc
+R f415b0a9be4e26d1aeb927a138261bed
 U drh
-Z 780f279750b73ad9a07ce3a651ba66ad
+Z dbc2b5253d321af49bf9c502e3a1dded

manifest.uuid

@@ -1 +1 @@
-bee73d429cb0e99b43fb191ac15e298d0353b135
+142b048ac778620dd4e448c2e969982eb8188501

src/wherecode.c

@@ -669,8 +669,9 @@ static int codeCursorHintFixExpr(Walker *pWalker, Expr *pExpr){
 ** Insert an OP_CursorHint instruction if it is appropriate to do so.
 */
 static void codeCursorHint(
-  WhereInfo *pWInfo,
+  WhereInfo *pWInfo,    /* The where clause */
-  WhereLevel *pLevel
+  WhereLevel *pLevel,   /* Which loop to provide hints for */
+  WhereTerm *pEndRange  /* Hint this end-of-scan boundary term if not NULL */
 ){
   Parse *pParse = pWInfo->pParse;
   sqlite3 *db = pParse->db;
@@ -680,7 +681,8 @@ static void codeCursorHint(
   int iCur;
   WhereClause *pWC;
   WhereTerm *pTerm;
-  int i;
+  WhereLoop *pWLoop;
+  int i, j;
   struct CCurHint sHint;
   Walker sWalker;
 
@@ -694,18 +696,33 @@ static void codeCursorHint(
   sWalker.pParse = pParse;
   sWalker.u.pCCurHint = &sHint;
   pWC = &pWInfo->sWC;
+  pWLoop = pLevel->pWLoop;
   for(i=0; i<pWC->nTerm; i++){
     pTerm = &pWC->a[i];
     if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
     if( pTerm->prereqAll & pLevel->notReady ) continue;
     if( ExprHasProperty(pTerm->pExpr, EP_FromJoin) ) continue;
+
+    /* All terms in pWLoop->aLTerm[] except pEndRange are used to initialize
+    ** the cursor.  No need to hint initialization terms. */
+    if( pTerm!=pEndRange ){
+      for(j=0; j<pWLoop->nLTerm && pWLoop->aLTerm[j]!=pTerm; j++){}
+      if( j<pWLoop->nLTerm ) continue;
+    }
+
+    /* No subqueries or non-deterministic functions allowed */
     if( sqlite3ExprContainsSubquery(pTerm->pExpr) ) continue;
+
+    /* For an index scan, make sure referenced columns are actually in
+    ** the index. */
     if( sHint.pIdx!=0 ){
       sWalker.eCode = 0;
       sWalker.xExprCallback = codeCursorHintCheckExpr;
       sqlite3WalkExpr(&sWalker, pTerm->pExpr);
       if( sWalker.eCode ) continue;
     }
+
+    /* If we survive all prior tests, that means this term is worth hinting */
     pExpr = sqlite3ExprAnd(db, pExpr, sqlite3ExprDup(db, pTerm->pExpr, 0));
   }
   if( pExpr!=0 ){
@@ -717,7 +734,7 @@ static void codeCursorHint(
   }
 }
 #else
-# define codeCursorHint(A,B)  /* No-op */
+# define codeCursorHint(A,B,C)  /* No-op */
 #endif /* SQLITE_ENABLE_CURSOR_HINTS */
 
 /*
@@ -883,7 +900,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
       pStart = pEnd;
       pEnd = pTerm;
     }
-    codeCursorHint(pWInfo, pLevel);
+    codeCursorHint(pWInfo, pLevel, pEnd);
     if( pStart ){
       Expr *pX;             /* The expression that defines the start bound */
       int r1, rTemp;        /* Registers for holding the start boundary */
@@ -1106,7 +1123,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
     start_constraints = pRangeStart || nEq>0;
 
     /* Seek the index cursor to the start of the range. */
-    codeCursorHint(pWInfo, pLevel);
+    codeCursorHint(pWInfo, pLevel, pRangeEnd);
     nConstraint = nEq;
     if( pRangeStart ){
       Expr *pRight = pRangeStart->pExpr->pRight;
@@ -1534,7 +1551,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
       ** a pseudo-cursor.  No need to Rewind or Next such cursors. */
       pLevel->op = OP_Noop;
     }else{
-      codeCursorHint(pWInfo, pLevel);
+      codeCursorHint(pWInfo, pLevel, 0);
       pLevel->op = aStep[bRev];
       pLevel->p1 = iCur;
       pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);

test/cursorhint.test

@@ -94,13 +94,18 @@ do_test 3.2 {
 
 # Indexed queries
 #
-do_test 4.1 {
+do_test 4.1asc {
   db eval {
     CREATE INDEX t1bc ON t1(b,c);
     CREATE INDEX t2yz ON t2(y,z);
   }
   p4_of_opcode db CursorHint {
-    SELECT * FROM t1 WHERE b>11;
+    SELECT * FROM t1 WHERE b>11 ORDER BY b ASC;
+  }
+} {}
+do_test 4.1desc {
+  p4_of_opcode db CursorHint {
+    SELECT * FROM t1 WHERE b>11 ORDER BY b DESC;
   }
 } {GT(c0,11)}
 do_test 4.2 {
@@ -108,16 +113,41 @@ do_test 4.2 {
     SELECT * FROM t1 WHERE b>11;
   }
 } {02 00}
-do_test 4.3 {
+do_test 4.3asc {
   p4_of_opcode db CursorHint {
-    SELECT c FROM t1 WHERE b>11;
+    SELECT c FROM t1 WHERE b<11 ORDER BY b ASC;
   }
-} {GT(c0,11)}
+} {LT(c0,11)}
+do_test 4.3desc {
+  p4_of_opcode db CursorHint {
+    SELECT c FROM t1 WHERE b<11 ORDER BY b DESC;
+  }
+} {}
 do_test 4.4 {
   p5_of_opcode db OpenRead . {
-    SELECT c FROM t1 WHERE b>11;
+    SELECT c FROM t1 WHERE b<11;
   }
 } {00}
 
+do_test 4.5asc {
+  p4_of_opcode db CursorHint {
+    SELECT c FROM t1 WHERE b>=10 AND b<=20 ORDER BY b ASC;
+  }
+} {LE(c0,20)}
+do_test 4.5desc {
+  p4_of_opcode db CursorHint {
+    SELECT c FROM t1 WHERE b>=10 AND b<=20 ORDER BY b DESC;
+  }
+} {GE(c0,10)}
+do_test 4.6asc {
+  p4_of_opcode db CursorHint {
+    SELECT rowid FROM t1 WHERE b=22 AND c>=10 AND c<=20 ORDER BY b,c ASC;
+  }
+} {LE(c1,20)}
+do_test 4.6desc {
+  p4_of_opcode db CursorHint {
+    SELECT rowid FROM t1 WHERE b=22 AND c>=10 AND c<=20 ORDER BY b,c DESC;
+  }
+} {GE(c1,10)}
 
 finish_test