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Experimental changes to improve the performance of OP_Next.

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FossilOrigin-Name: 1a249845251199c00817893add300a1a654b4df9
This commit is contained in:
dan
2011-08-27 18:48:57 +00:00
parent 3d4435b234
commit a205a486d2
6 changed files with 60 additions and 41 deletions
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45
src/vdbe.c
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@@ -2550,7 +2550,7 @@ case OP_Count: { /* out2-prerelease */
BtCursor *pCrsr;
pCrsr = p->apCsr[pOp->p1]->pCursor;
if( pCrsr ){
if( ALWAYS(pCrsr) ){
rc = sqlite3BtreeCount(pCrsr, &nEntry);
}else{
nEntry = 0;
@@ -3112,15 +3112,9 @@ case OP_OpenWrite: {
rc = sqlite3BtreeCursor(pX, p2, wrFlag, pKeyInfo, pCur->pCursor);
pCur->pKeyInfo = pKeyInfo;
/* Since it performs no memory allocation or IO, the only values that
** sqlite3BtreeCursor() may return are SQLITE_EMPTY and SQLITE_OK.
** SQLITE_EMPTY is only returned when attempting to open the table
** rooted at page 1 of a zero-byte database. */
assert( rc==SQLITE_EMPTY || rc==SQLITE_OK );
if( rc==SQLITE_EMPTY ){
pCur->pCursor = 0;
rc = SQLITE_OK;
}
/* Since it performs no memory allocation or IO, the only value that
** sqlite3BtreeCursor() may return is SQLITE_OK. */
assert( rc==SQLITE_OK );
/* Set the VdbeCursor.isTable and isIndex variables. Previous versions of
** SQLite used to check if the root-page flags were sane at this point
@@ -3333,7 +3327,7 @@ case OP_SeekGt: { /* jump, in3 */
assert( OP_SeekGe == OP_SeekLt+2 );
assert( OP_SeekGt == OP_SeekLt+3 );
assert( pC->isOrdered );
if( pC->pCursor!=0 ){
if( ALWAYS(pC->pCursor!=0) ){
oc = pOp->opcode;
pC->nullRow = 0;
if( pC->isTable ){
@@ -3691,7 +3685,7 @@ case OP_NotExists: { /* jump, in3 */
assert( pC->isTable );
assert( pC->pseudoTableReg==0 );
pCrsr = pC->pCursor;
if( pCrsr!=0 ){
if( ALWAYS(pCrsr!=0) ){
res = 0;
iKey = pIn3->u.i;
rc = sqlite3BtreeMovetoUnpacked(pCrsr, 0, iKey, 0, &res);
@@ -4218,6 +4212,7 @@ case OP_NullRow: {
assert( pC!=0 );
pC->nullRow = 1;
pC->rowidIsValid = 0;
assert( pC->pCursor || pC->pVtabCursor );
if( pC->pCursor ){
sqlite3BtreeClearCursor(pC->pCursor);
}
@@ -4241,7 +4236,7 @@ case OP_Last: { /* jump */
pC = p->apCsr[pOp->p1];
assert( pC!=0 );
pCrsr = pC->pCursor;
if( pCrsr==0 ){
if( NEVER(pCrsr==0) ){
res = 1;
}else{
rc = sqlite3BtreeLast(pCrsr, &res);
@@ -4296,7 +4291,9 @@ case OP_Rewind: { /* jump */
res = 1;
if( isSorter(pC) ){
rc = sqlite3VdbeSorterRewind(db, pC, &res);
}else if( (pCrsr = pC->pCursor)!=0 ){
}else{
pCrsr = pC->pCursor;
assert( pCrsr );
rc = sqlite3BtreeFirst(pCrsr, &res);
pC->atFirst = res==0 ?1:0;
pC->deferredMoveto = 0;
@@ -4311,7 +4308,7 @@ case OP_Rewind: { /* jump */
break;
}
/* Opcode: Next P1 P2 * * P5
/* Opcode: Next P1 P2 * P4 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
@@ -4320,6 +4317,9 @@ case OP_Rewind: { /* jump */
**
** The P1 cursor must be for a real table, not a pseudo-table.
**
** P4 is always of type P4_ADVANCE. The function pointer points to
** sqlite3BtreeNext().
**
** If P5 is positive and the jump is taken, then event counter
** number P5-1 in the prepared statement is incremented.
**
@@ -4334,13 +4334,15 @@ case OP_Rewind: { /* jump */
**
** The P1 cursor must be for a real table, not a pseudo-table.
**
** 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.
*/
case OP_Prev: /* jump */
case OP_Next: { /* jump */
VdbeCursor *pC;
BtCursor *pCrsr;
int res;
CHECK_FOR_INTERRUPT;
@@ -4354,15 +4356,12 @@ case OP_Next: { /* jump */
assert( pOp->opcode==OP_Next );
rc = sqlite3VdbeSorterNext(db, pC, &res);
}else{
pCrsr = pC->pCursor;
if( pCrsr==0 ){
pC->nullRow = 1;
break;
}
res = 1;
assert( pC->deferredMoveto==0 );
rc = pOp->opcode==OP_Next ? sqlite3BtreeNext(pCrsr, &res) :
sqlite3BtreePrevious(pCrsr, &res);
assert( pC->pCursor );
assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );
rc = pOp->p4.xAdvance(pC->pCursor, &res);
}
pC->nullRow = (u8)res;
pC->cacheStatus = CACHE_STALE;