Provide hints to the btree layer Next and Previous primitives to let them

know if they can be no-ops if the underlying index is unique.

FossilOrigin-Name: a2c347faf91d82cf8734621bf378a6dd68b00957

diff --git a/manifest b/manifest
index 969f59f8d9a6b629f958ab9f164e6d98dea58a1f..a6cc0a1a6e98eee5cc751e6bfc26d85a82d266f4 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Merge\srecent\sfixes\sfrom\strunk.\s\sCherrypick\sof\s[c43b59dac1],\s[a221aa82bb],\s[e1eba1fb09],\sand\s[1e131094b5].
-D 2014-01-15T00:24:22.522
+C Provide\shints\sto\sthe\sbtree\slayer\sNext\sand\sPrevious\sprimitives\sto\slet\sthem\s\nknow\sif\sthey\scan\sbe\sno-ops\sif\sthe\sunderlying\sindex\sis\sunique.
+D 2014-01-28T00:49:55.352
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in e1a9b4258bbde53f5636f4e238c65b7e11459e2b
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -166,7 +166,7 @@ F src/auth.c 523da7fb4979469955d822ff9298352d6b31de34
 F src/backup.c 1809a7caa2504233bdddd12f5018422421789537
 F src/bitvec.c 19a4ba637bd85f8f63fc8c9bae5ade9fb05ec1cb
 F src/btmutex.c 976f45a12e37293e32cae0281b15a21d48a8aaa7
-F src/btree.c fe6c95c57fd14ed4b3329f4b5bb08132fe7c322d
+F src/btree.c c695c10622607d483ce435506420c99443a6b22c
 F src/btree.h a61ddebc78c66795a2b93181321a116746302cc9
 F src/btreeInt.h f038e818bfadf75afbd09819ed93c26a333d39e0
 F src/build.c 1965c7b596ca6295b7ca59541ad186c57564b8f7
@@ -280,7 +280,7 @@ F src/update.c d1c2477dcf14d90999d1935af4efb4806553250b
 F src/utf.c 6fc6c88d50448c469c5c196acf21617a24f90269
 F src/util.c 76ed0519296e3f62e97e57dab1999e34184c8e49
 F src/vacuum.c 3728d74919d4fb1356f9e9a13e27773db60b7179
-F src/vdbe.c 54894fde8dc806d259e015ac7c9680145e725835
+F src/vdbe.c 73d27c705888814069f311aa5f7ca0281a98b628
 F src/vdbe.h c06f0813f853566457ce9cfb1a4a4bc39a5da644
 F src/vdbeInt.h 05fbda0e061dbc4aaa2709a8cccf3515c245b263
 F src/vdbeapi.c 93a22a9ba2abe292d5c2cf304d7eb2e894dde0ed
@@ -293,8 +293,8 @@ F src/vtab.c 21b932841e51ebd7d075e2d0ad1415dce8d2d5fd
 F src/wal.c 7dc3966ef98b74422267e7e6e46e07ff6c6eb1b4
 F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
 F src/walker.c e9e593d5bb798c3e67fc3893dfe7055c9e7d8d74
-F src/where.c 3b589eee28271c4a7cbdb11f0312e1dc2013c255
-F src/whereInt.h 96a75c61f1d2b9d4a8e4bb17d89deb0cf7cba358
+F src/where.c 549067bd1c78072d86a3fc48d86d549bb5b29b8d
+F src/whereInt.h 921f935af8b684ffb49705610bda7284db1db138
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
 F test/aggnested.test 45c0201e28045ad38a530b5a144b73cd4aa2cfd6
@@ -1145,11 +1145,7 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P ac5852d6403c9c9628ca0aa7be135c702f000698
-Q +1e131094b522103a0829f72193b067b04e42ce82
-Q +a221aa82bb5496885fd0bf76e4601443799511de
-Q +c43b59dac1fbb67ec3a9d921005543046ad416ce
-Q +e1eba1fb09d7db49d77928bd115b27b8002ae640
-R 9a2615403bfd61ea9575eeff6c57728d
-U mistachkin
-Z 9a636fd2c05ad5aa90446f6df2e80da4
+P c697d2f83c2d8ea0a100b84b0debb6a322c3a876
+R 98f94a08f2da89f2a3296169c5e6a07d
+U drh
+Z b8a82ebf9ab9cd1246e1fd5c1b9c1901

diff --git a/manifest.uuid b/manifest.uuid
index a70c5b7ce1f459d393faf23f6fa6fb449b52b745..c41e5a42685903b1e16531509afad770e1847bb0 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-c697d2f83c2d8ea0a100b84b0debb6a322c3a876
\ No newline at end of file
+a2c347faf91d82cf8734621bf378a6dd68b00957
\ No newline at end of file

diff --git a/src/btree.c b/src/btree.c
index 30fdf4256fa7b726af1e1b1323a387e687fd7997..da01a7ae8c121006a916a7cfada90e670da8bb37 100644 (file)
--- a/src/btree.c
+++ b/src/btree.c
@@ -4817,6 +4817,15 @@ int sqlite3BtreeEof(BtCursor *pCur){
 ** successful then set *pRes=0.  If the cursor
 ** was already pointing to the last entry in the database before
 ** this routine was called, then set *pRes=1.
+**
+** The calling function will set *pRes to 0 or 1.  The initial *pRes value
+** will be 1 if the cursor being stepped corresponds to an SQL index and
+** if this routine could have been skipped if that SQL index had been
+** a unique index.  Otherwise the caller will have set *pRes to zero.
+** Zero is the common case. The btree implementation is free to use the
+** initial *pRes value as a hint to improve performance, but the current
+** SQLite btree implementation does not. (Note that the comdb2 btree
+** implementation does use this hint, however.)
 */
 int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
   int rc;
@@ -4825,6 +4834,7 @@ int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
 
   assert( cursorHoldsMutex(pCur) );
   assert( pRes!=0 );
+  assert( *pRes==0 || *pRes==1 );
   assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
   if( pCur->eState!=CURSOR_VALID ){
     rc = restoreCursorPosition(pCur);
@@ -4903,6 +4913,15 @@ int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
 ** successful then set *pRes=0.  If the cursor
 ** was already pointing to the first entry in the database before
 ** this routine was called, then set *pRes=1.
+**
+** The calling function will set *pRes to 0 or 1.  The initial *pRes value
+** will be 1 if the cursor being stepped corresponds to an SQL index and
+** if this routine could have been skipped if that SQL index had been
+** a unique index.  Otherwise the caller will have set *pRes to zero.
+** Zero is the common case. The btree implementation is free to use the
+** initial *pRes value as a hint to improve performance, but the current
+** SQLite btree implementation does not. (Note that the comdb2 btree
+** implementation does use this hint, however.)
 */
 int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
   int rc;
@@ -4910,6 +4929,7 @@ int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
 
   assert( cursorHoldsMutex(pCur) );
   assert( pRes!=0 );
+  assert( *pRes==0 || *pRes==1 );
   assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
   pCur->atLast = 0;
   if( pCur->eState!=CURSOR_VALID ){
@@ -7150,7 +7170,7 @@ int sqlite3BtreeDelete(BtCursor *pCur){
   ** sub-tree headed by the child page of the cell being deleted. This makes
   ** balancing the tree following the delete operation easier.  */
   if( !pPage->leaf ){
-    int notUsed;
+    int notUsed = 0;
     rc = sqlite3BtreePrevious(pCur, &notUsed);
     if( rc ) return rc;
   }

diff --git a/src/vdbe.c b/src/vdbe.c
index 8ae4ce484cb13131dbb1bb2c516ae4f139f15f34..9ce8422344171e873c46dd9ddfc7ec647ece4466 100644 (file)
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -3580,6 +3580,7 @@ case OP_SeekGt: {       /* jump, in3 */
 #endif
   if( oc>=OP_SeekGe ){  assert( oc==OP_SeekGe || oc==OP_SeekGt );
     if( res<0 || (res==0 && oc==OP_SeekGt) ){
+      res = 0;
       rc = sqlite3BtreeNext(pC->pCursor, &res);
       if( rc!=SQLITE_OK ) goto abort_due_to_error;
       pC->rowidIsValid = 0;
@@ -3589,6 +3590,7 @@ case OP_SeekGt: {       /* jump, in3 */
   }else{
     assert( oc==OP_SeekLt || oc==OP_SeekLe );
     if( res>0 || (res==0 && oc==OP_SeekLt) ){
+      res = 0;
       rc = sqlite3BtreePrevious(pC->pCursor, &res);
       if( rc!=SQLITE_OK ) goto abort_due_to_error;
       pC->rowidIsValid = 0;
@@ -4442,7 +4444,7 @@ case OP_Rewind: {        /* jump */
   break;
 }
 
-/* Opcode: Next P1 P2 * * P5
+/* Opcode: Next P1 P2 P3 * P5
 **
 ** Advance cursor P1 so that it points to the next key/data pair in its
 ** table or index.  If there are no more key/value pairs then fall through
@@ -4452,6 +4454,11 @@ case OP_Rewind: {        /* jump */
 ** The P1 cursor must be for a real table, not a pseudo-table.  P1 must have
 ** been opened prior to this opcode or the program will segfault.
 **
+** The P3 value is a hint to the btree implementation. If P3==1, that
+** means P1 is an SQL index and that this instruction could have been
+** omitted if that index had been unique.  P3 is usually 0.  P3 is
+** always either 0 or 1.
+**
 ** P4 is always of type P4_ADVANCE. The function pointer points to
 ** sqlite3BtreeNext().
 **
@@ -4460,12 +4467,12 @@ case OP_Rewind: {        /* jump */
 **
 ** See also: Prev, NextIfOpen
 */
-/* Opcode: NextIfOpen P1 P2 * * P5
+/* Opcode: NextIfOpen P1 P2 P3 * P5
 **
 ** This opcode works just like OP_Next except that if cursor P1 is not
 ** open it behaves a no-op.
 */
-/* Opcode: Prev P1 P2 * * P5
+/* Opcode: Prev P1 P2 P3 * P5
 **
 ** Back up cursor P1 so that it points to the previous key/data pair in its
 ** table or index.  If there is no previous key/value pairs then fall through
@@ -4475,13 +4482,18 @@ case OP_Rewind: {        /* jump */
 ** The P1 cursor must be for a real table, not a pseudo-table.  If P1 is
 ** not open then the behavior is undefined.
 **
+** The P3 value is a hint to the btree implementation. If P3==1, that
+** means P1 is an SQL index and that this instruction could have been
+** omitted if that index had been unique.  P3 is usually 0.  P3 is
+** always either 0 or 1.
+**
 ** P4 is always of type P4_ADVANCE. The function pointer points to
 ** sqlite3BtreePrevious().
 **
 ** If P5 is positive and the jump is taken, then event counter
 ** number P5-1 in the prepared statement is incremented.
 */
-/* Opcode: PrevIfOpen P1 P2 * * P5
+/* Opcode: PrevIfOpen P1 P2 P3 * P5
 **
 ** This opcode works just like OP_Prev except that if cursor P1 is not
 ** open it behaves a no-op.
@@ -4503,9 +4515,12 @@ case OP_Next:          /* jump */
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   assert( pOp->p5<ArraySize(p->aCounter) );
   pC = p->apCsr[pOp->p1];
+  res = pOp->p3;
   assert( pC!=0 );
   assert( pC->deferredMoveto==0 );
   assert( pC->pCursor );
+  assert( res==0 || (res==1 && pC->isTable==0) );
+  testcase( res==1 );
   assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
   assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );
   assert( pOp->opcode!=OP_NextIfOpen || pOp->p4.xAdvance==sqlite3BtreeNext );

diff --git a/src/where.c b/src/where.c
index cfbf769c67fdd0e0890e9b2aa93e047813bf3892..34bbf7ee472f7d0c41998eb977d04148ef1af4a8 100644 (file)
--- a/src/where.c
+++ b/src/where.c
@@ -3182,6 +3182,8 @@ static Bitmask codeOneLoopStart(
       pLevel->op = OP_Next;
     }
     pLevel->p1 = iIdxCur;
+    assert( (WHERE_UNQ_WANTED>>16)==1 );
+    pLevel->p3 = (pLoop->wsFlags>>16)&1;
     if( (pLoop->wsFlags & WHERE_CONSTRAINT)==0 ){
       pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
     }else{
@@ -3978,12 +3980,13 @@ static int whereLoopAddBtreeIndex(
         || nInMul==0
       );
       pNew->wsFlags |= WHERE_COLUMN_EQ;
-      if( iCol<0  
-       || (pProbe->onError!=OE_None && nInMul==0
-           && pNew->u.btree.nEq==pProbe->nKeyCol-1)
-      ){
+      if( iCol<0 || (nInMul==0 && pNew->u.btree.nEq==pProbe->nKeyCol-1)){
         assert( (pNew->wsFlags & WHERE_COLUMN_IN)==0 || iCol<0 );
-        pNew->wsFlags |= WHERE_ONEROW;
+        if( iCol>=0 && pProbe->onError==OE_None ){
+          pNew->wsFlags |= WHERE_UNQ_WANTED;
+        }else{
+          pNew->wsFlags |= WHERE_ONEROW;
+        }
       }
       pNew->u.btree.nEq++;
       pNew->nOut = nRowEst + nInMul;
@@ -5773,7 +5776,7 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
     pLoop = pLevel->pWLoop;
     sqlite3VdbeResolveLabel(v, pLevel->addrCont);
     if( pLevel->op!=OP_Noop ){
-      sqlite3VdbeAddOp2(v, pLevel->op, pLevel->p1, pLevel->p2);
+      sqlite3VdbeAddOp3(v, pLevel->op, pLevel->p1, pLevel->p2, pLevel->p3);
       sqlite3VdbeChangeP5(v, pLevel->p5);
     }
     if( pLoop->wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){

diff --git a/src/whereInt.h b/src/whereInt.h
index 56646c55e6102b8b81d6b9daa86f6b9e83787c27..23f929c4610030022c5e37e688b1602c7ae27a27 100644 (file)
--- a/src/whereInt.h
+++ b/src/whereInt.h
@@ -70,7 +70,7 @@ struct WhereLevel {
   int addrFirst;        /* First instruction of interior of the loop */
   int addrBody;         /* Beginning of the body of this loop */
   u8 iFrom;             /* Which entry in the FROM clause */
-  u8 op, p5;            /* Opcode and P5 of the opcode that ends the loop */
+  u8 op, p3, p5;        /* Opcode, P3 & P5 of the opcode that ends the loop */
   int p1, p2;           /* Operands of the opcode used to ends the loop */
   union {               /* Information that depends on pWLoop->wsFlags */
     struct {
@@ -457,3 +457,4 @@ struct WhereInfo {
 #define WHERE_MULTI_OR     0x00002000  /* OR using multiple indices */
 #define WHERE_AUTO_INDEX   0x00004000  /* Uses an ephemeral index */
 #define WHERE_SKIPSCAN     0x00008000  /* Uses the skip-scan algorithm */
+#define WHERE_UNQ_WANTED   0x00010000  /* WHERE_ONEROW would have been helpful*/