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Performance optimization to the OP_Next and OP_Prev opcodes.

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FossilOrigin-Name: ecaac28a2e78aca148fc614fe54bf2706aed8be2
This commit is contained in:
drh
2013-11-21 03:12:25 +00:00
parent 3630a408f2
commit f93cd949a0
5 changed files with 51 additions and 34 deletions
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60
src/vdbe.c
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@@ -4467,7 +4467,8 @@ case OP_Rewind: { /* jump */
** to the following instruction. But if the cursor advance was successful,
** jump immediately to P2.
**
** The P1 cursor must be for a real table, not a pseudo-table.
** 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.
**
** P4 is always of type P4_ADVANCE. The function pointer points to
** sqlite3BtreeNext().
@@ -4475,7 +4476,12 @@ case OP_Rewind: { /* jump */
** If P5 is positive and the jump is taken, then event counter
** number P5-1 in the prepared statement is incremented.
**
** See also: Prev
** See also: Prev, NextIfOpen
*/
/* Opcode: NextIfOpen P1 P2 * * 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
**
@@ -4484,7 +4490,8 @@ case OP_Rewind: { /* jump */
** to the following instruction. But if the cursor backup was successful,
** jump immediately to P2.
**
** The P1 cursor must be for a real table, not a pseudo-table.
** The P1 cursor must be for a real table, not a pseudo-table. If P1 is
** not open then the behavior is undefined.
**
** P4 is always of type P4_ADVANCE. The function pointer points to
** sqlite3BtreePrevious().
@@ -4492,38 +4499,47 @@ case OP_Rewind: { /* jump */
** If P5 is positive and the jump is taken, then event counter
** number P5-1 in the prepared statement is incremented.
*/
case OP_SorterNext: /* jump */
case OP_Prev: /* jump */
case OP_Next: { /* jump */
/* Opcode: PrevIfOpen P1 P2 * * P5
**
** This opcode works just like OP_Prev except that if cursor P1 is not
** open it behaves a no-op.
*/
case OP_SorterNext: { /* jump */
VdbeCursor *pC;
int res;
pC = p->apCsr[pOp->p1];
assert( isSorter(pC) );
rc = sqlite3VdbeSorterNext(db, pC, &res);
goto next_tail;
case OP_PrevIfOpen: /* jump */
case OP_NextIfOpen: /* jump */
if( p->apCsr[pOp->p1]==0 ) break;
/* Fall through */
case OP_Prev: /* jump */
case OP_Next: /* jump */
assert( pOp->p1>=0 && pOp->p1<p->nCursor );
assert( pOp->p5<ArraySize(p->aCounter) );
pC = p->apCsr[pOp->p1];
if( pC==0 ){
break; /* See ticket #2273 */
}
assert( isSorter(pC)==(pOp->opcode==OP_SorterNext) );
if( isSorter(pC) ){
assert( pOp->opcode==OP_SorterNext );
rc = sqlite3VdbeSorterNext(db, pC, &res);
}else{
/* res = 1; // Always initialized by the xAdvance() call */
assert( pC->deferredMoveto==0 );
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;
assert( pC!=0 );
assert( pC->deferredMoveto==0 );
assert( pC->pCursor );
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 );
assert( pOp->opcode!=OP_PrevIfOpen || pOp->p4.xAdvance==sqlite3BtreePrevious);
rc = pOp->p4.xAdvance(pC->pCursor, &res);
next_tail:
pC->cacheStatus = CACHE_STALE;
if( res==0 ){
pC->nullRow = 0;
pc = pOp->p2 - 1;
p->aCounter[pOp->p5]++;
#ifdef SQLITE_TEST
sqlite3_search_count++;
#endif
}else{
pC->nullRow = 1;
}
pC->rowidIsValid = 0;
goto check_for_interrupt;