Avoid a test for CURTYPE_BTREE in sqlite3VdbeCursorMoveto() in order to reduce

the size and improve the performance of OP_Column.

FossilOrigin-Name: f078deb25149b7b1881b7f3374b343d0677e82336d8fdd7f1cdd06d926b5dd57

manifest

@@ -1,5 +1,5 @@
-C Remove\san\sunnecessary\slocal\svariable\sfrom\sOP_Column,\sfor\sa\ssmall\ssize\nreduction\sand\sperformance\sincrease.
-D 2017-08-16T14:16:19.879
+C Avoid\sa\stest\sfor\sCURTYPE_BTREE\sin\ssqlite3VdbeCursorMoveto()\sin\sorder\sto\sreduce\nthe\ssize\sand\simprove\sthe\sperformance\sof\sOP_Column.
+D 2017-08-16T19:20:20.392
 F Makefile.in d9873c9925917cca9990ee24be17eb9613a668012c85a343aef7e5536ae266e8
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 02b469e9dcd5b7ee63fc1fb05babc174260ee4cfa4e0ef2e48c3c6801567a016
@@ -397,9 +397,9 @@ F src/auth.c 79f96c6f33bf0e5da8d1c282cee5ebb1852bb8a6ccca3e485d7c459b035d9c3c
 F src/backup.c faf17e60b43233c214aae6a8179d24503a61e83b
 F src/bitvec.c 17ea48eff8ba979f1f5b04cc484c7bb2be632f33
 F src/btmutex.c 0e9ce2d56159b89b9bc8e197e023ee11e39ff8ca
-F src/btree.c d2f5f347e56f8b7ed1bb798087045a3b98cd63f45fde7675fd24b9e88b61304d
-F src/btree.h 3edc5329bc59534d2d15b4f069a9f54b779a7e51289e98fa481ae3c0e526a5ca
-F src/btreeInt.h f78671f594dafd88cf9a81253da04db81272b382d2dc074bb983d348b95d9d2d
+F src/btree.c e1a98bef27d6189df5c5b8b3c9b5e53d6b74bf9a936af97757c21e9ea6a5c6b2
+F src/btree.h 32ef5d3f25dc70ef1ee9cecf84a023c21378f06a57cd701d2e866e141b150f09
+F src/btreeInt.h 55b702efce17e5d1941865464227d3802cfc9c7c832fac81d4c94dced47a71fc
 F src/build.c f8a85d2ad14c2201e10c2fe7185e1cb3f1db8b0c90d40d1fb99c20b135ab71bc
 F src/callback.c 930648a084a3adc741c6471adfbdc50ba47ba3542421cb80a26f259f467de65e
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
@@ -522,11 +522,11 @@ F src/update.c 5404be9e840717323a69209190cdbc9d0d34adaedaaf1d1a1069babf2c4171c0
 F src/utf.c 810fbfebe12359f10bc2a011520a6e10879ab2a163bcb26c74768eab82ea62a5
 F src/util.c fc081ec6f63448dcd80d3dfad35baecfa104823254a815b081a4d9fe76e1db23
 F src/vacuum.c 90839322fd5f00df9617eb21b68beda9b6e2a2937576b0d65985e4aeb1c53739
-F src/vdbe.c c8e7bec8764b26b8e80fadffab2b9c18e8ed5ab2e92d1be5a7aebeed18ca8be5
+F src/vdbe.c 711a1b2c0a6046483ebf4ac43c4c0ea5bef3e50534a4ab9e1d7e3542635cd009
 F src/vdbe.h d50cadf12bcf9fb99117ef392ce1ea283aa429270481426b6e8b0280c101fd97
-F src/vdbeInt.h ff2b7db0968d20e6184aee256d2e535d565f5a172e3588a78adb166a41fc4911
+F src/vdbeInt.h 1fe00770144c12c4913128f35262d11527ef3284561baaab59b947a41c08d0d9
 F src/vdbeapi.c 05d6b14ab73952db0d73f6452d6960216997bd966a710266b2fe051f25326abc
-F src/vdbeaux.c 1bef372f59f9e1dba5ead70cc5c24bf978bab0b9fdc2f69692afaa3a2d4dd8f3
+F src/vdbeaux.c 1f15018ef7abe22669967f70b02bfe6709be403f126f713dabb091b9d631859a
 F src/vdbeblob.c db3cf91060f6f4b2f1358a4200e844697990752177784c7c95da00b7ac9f1c7b
 F src/vdbemem.c b7fac20534c79b7554dab2e8a180c585a8bc1b9c85149d1b2d9746cf314d06ed
 F src/vdbesort.c fea2bea25f5e9ccd91e0760d7359f0365f9fba1aaeac7216c71cad78765f58e3
@@ -1647,7 +1647,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P dc98a92f32511ee322b0207bd286e967248a8e59b418f11168eb31e34b0fa0fa
-R 8dc9658e95fe266a68d077704d4afe1a
+P 39543903282409ad3f139f8a0bb376661e7595a33af4f647945b1513a028ccb4
+R 6446f3c323d2c08f3899473bfc8c1574
 U drh
-Z 4fdaa02107e5a271b3b6d501790c7a7c
+Z 68326b6d5ed2188a1ee820e19559d5ac

manifest.uuid

@@ -1 +1 @@
-39543903282409ad3f139f8a0bb376661e7595a33af4f647945b1513a028ccb4
+f078deb25149b7b1881b7f3374b343d0677e82336d8fdd7f1cdd06d926b5dd57

src/btree.c

@@ -838,6 +838,17 @@ int sqlite3BtreeCursorHasMoved(BtCursor *pCur){
   return pCur->eState!=CURSOR_VALID;
 }
 
+/*
+** Return a pointer to a fake BtCursor object that will always answer
+** false to the sqlite3BtreeCursorHasMoved() routine above.  The fake
+** cursor returned must not be used with any other Btree interface.
+*/
+BtCursor *sqlite3BtreeFakeValidCursor(void){
+  static u8 fakeCursor = CURSOR_VALID;
+  assert( offsetof(BtCursor, eState)==0 );
+  return (BtCursor*)&fakeCursor;
+}
+
 /*
 ** This routine restores a cursor back to its original position after it
 ** has been moved by some outside activity (such as a btree rebalance or

src/btree.h

@@ -230,6 +230,7 @@ int sqlite3BtreeCursor(
   struct KeyInfo*,                     /* First argument to compare function */
   BtCursor *pCursor                    /* Space to write cursor structure */
 );
+BtCursor *sqlite3BtreeFakeValidCursor(void);
 int sqlite3BtreeCursorSize(void);
 void sqlite3BtreeCursorZero(BtCursor*);
 void sqlite3BtreeCursorHintFlags(BtCursor*, unsigned);

src/btreeInt.h

@@ -499,6 +499,11 @@ struct CellInfo {
 **    eState==FAULT:                   Cursor fault with skipNext as error code.
 */
 struct BtCursor {
+  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
+  u8 curFlags;              /* zero or more BTCF_* flags defined below */
+  u8 curPagerFlags;         /* Flags to send to sqlite3PagerGet() */
+  u8 hints;                 /* As configured by CursorSetHints() */
+  int nOvflAlloc;           /* Allocated size of aOverflow[] array */
   Btree *pBtree;            /* The Btree to which this cursor belongs */
   BtShared *pBt;            /* The BtShared this cursor points to */
   BtCursor *pNext;          /* Forms a linked list of all cursors */
@@ -507,13 +512,8 @@ struct BtCursor {
   i64 nKey;                 /* Size of pKey, or last integer key */
   void *pKey;               /* Saved key that was cursor last known position */
   Pgno pgnoRoot;            /* The root page of this tree */
-  int nOvflAlloc;           /* Allocated size of aOverflow[] array */
   int skipNext;    /* Prev() is noop if negative. Next() is noop if positive.
                    ** Error code if eState==CURSOR_FAULT */
-  u8 curFlags;              /* zero or more BTCF_* flags defined below */
-  u8 curPagerFlags;         /* Flags to send to sqlite3PagerGet() */
-  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
-  u8 hints;                 /* As configured by CursorSetHints() */
   /* All fields above are zeroed when the cursor is allocated.  See
   ** sqlite3BtreeCursorZero().  Fields that follow must be manually
   ** initialized. */

src/vdbe.c

@@ -2413,8 +2413,10 @@ case OP_Column: {
   if( pC->cacheStatus!=p->cacheCtr ){                /*OPTIMIZATION-IF-FALSE*/
     if( pC->nullRow ){
       if( pC->eCurType==CURTYPE_PSEUDO ){
-        assert( pC->uc.pseudoTableReg>0 );
-        pReg = &aMem[pC->uc.pseudoTableReg];
+        /* For the special case of as pseudo-cursor, the seekResult field
+        ** identifies the register that holds the record */
+        assert( pC->seekResult>0 );
+        pReg = &aMem[pC->seekResult];
         assert( pReg->flags & MEM_Blob );
         assert( memIsValid(pReg) );
         pC->payloadSize = pC->szRow = pReg->n;
@@ -3628,8 +3630,13 @@ case OP_OpenPseudo: {
   pCx = allocateCursor(p, pOp->p1, pOp->p3, -1, CURTYPE_PSEUDO);
   if( pCx==0 ) goto no_mem;
   pCx->nullRow = 1;
-  pCx->uc.pseudoTableReg = pOp->p2;
+  pCx->seekResult = pOp->p2;
   pCx->isTable = 1;
+  /* Give this pseudo-cursor a fake BtCursor pointer so that pCx
+  ** can be safely passed to sqlite3VdbeCursorMoveto().  This avoids a test
+  ** for pCx->eCurType==CURTYPE_BTREE inside of sqlite3VdbeCursorMoveto()
+  ** which is a performance optimization */
+  pCx->uc.pCursor = sqlite3BtreeFakeValidCursor();
   assert( pOp->p5==0 );
   break;
 }

src/vdbeInt.h

@@ -96,18 +96,18 @@ struct VdbeCursor {
   u32 cacheStatus;        /* Cache is valid if this matches Vdbe.cacheCtr */
   int seekResult;         /* Result of previous sqlite3BtreeMoveto() or 0
                           ** if there have been no prior seeks on the cursor. */
-  /* NB: seekResult does not distinguish between "no seeks have ever occurred
-  ** on this cursor" and "the most recent seek was an exact match". */
+  /* seekResult does not distinguish between "no seeks have ever occurred
+  ** on this cursor" and "the most recent seek was an exact match".
+  ** For CURTYPE_PSEUDO, seekResult is the register holding the record */
 
   /* When a new VdbeCursor is allocated, only the fields above are zeroed.
   ** The fields that follow are uninitialized, and must be individually
   ** initialized prior to first use. */
   VdbeCursor *pAltCursor; /* Associated index cursor from which to read */
   union {
-    BtCursor *pCursor;          /* CURTYPE_BTREE.  Btree cursor */
-    sqlite3_vtab_cursor *pVCur; /* CURTYPE_VTAB.   Vtab cursor */
-    int pseudoTableReg;         /* CURTYPE_PSEUDO. Reg holding content. */
-    VdbeSorter *pSorter;        /* CURTYPE_SORTER. Sorter object */
+    BtCursor *pCursor;          /* CURTYPE_BTREE or _PSEUDO.  Btree cursor */
+    sqlite3_vtab_cursor *pVCur; /* CURTYPE_VTAB.              Vtab cursor */
+    VdbeSorter *pSorter;        /* CURTYPE_SORTER.            Sorter object */
   } uc;
   KeyInfo *pKeyInfo;      /* Info about index keys needed by index cursors */
   u32 iHdrOffset;         /* Offset to next unparsed byte of the header */

src/vdbeaux.c

@@ -3139,19 +3139,18 @@ int sqlite3VdbeCursorRestore(VdbeCursor *p){
 */
 int sqlite3VdbeCursorMoveto(VdbeCursor **pp, int *piCol){
   VdbeCursor *p = *pp;
-  if( p->eCurType==CURTYPE_BTREE ){
-    if( p->deferredMoveto ){
-      int iMap;
-      if( p->aAltMap && (iMap = p->aAltMap[1+*piCol])>0 ){
-        *pp = p->pAltCursor;
-        *piCol = iMap - 1;
-        return SQLITE_OK;
-      }
-      return handleDeferredMoveto(p);
-    }
-    if( sqlite3BtreeCursorHasMoved(p->uc.pCursor) ){
-      return handleMovedCursor(p);
+  assert( p->eCurType==CURTYPE_BTREE || p->eCurType==CURTYPE_PSEUDO );
+  if( p->deferredMoveto ){
+    int iMap;
+    if( p->aAltMap && (iMap = p->aAltMap[1+*piCol])>0 ){
+      *pp = p->pAltCursor;
+      *piCol = iMap - 1;
+      return SQLITE_OK;
     }
+    return handleDeferredMoveto(p);
+  }
+  if( sqlite3BtreeCursorHasMoved(p->uc.pCursor) ){
+    return handleMovedCursor(p);
   }
   return SQLITE_OK;
 }