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Experimental attempt to make better use of covering indexes within OR queries.

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FossilOrigin-Name: a323ac3a9d42bd5cb38d724c7e1180584b91054c
This commit is contained in:
dan
2016-01-29 19:29:45 +00:00
parent 65875f37bc
commit de892d9660
7 changed files with 121 additions and 22 deletions
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20
src/vdbe.c
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@@ -2376,12 +2376,16 @@ case OP_Column: {
u32 t; /* A type code from the record header */
Mem *pReg; /* PseudoTable input register */
pC = p->apCsr[pOp->p1];
p2 = pOp->p2;
/* If the cursor cache is stale, bring it up-to-date */
rc = sqlite3VdbeCursorMoveto(&pC, &p2);
assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
pDest = &aMem[pOp->p3];
memAboutToChange(p, pDest);
assert( pOp->p1>=0 && pOp->p1<p->nCursor );
pC = p->apCsr[pOp->p1];
assert( pC!=0 );
assert( p2<pC->nField );
aOffset = pC->aOffset;
@@ -2390,8 +2394,6 @@ case OP_Column: {
assert( pC->eCurType!=CURTYPE_SORTER );
pCrsr = pC->uc.pCursor;
/* If the cursor cache is stale, bring it up-to-date */
rc = sqlite3VdbeCursorMoveto(pC);
if( rc ) goto abort_due_to_error;
if( pC->cacheStatus!=p->cacheCtr ){
if( pC->nullRow ){
@@ -3846,7 +3848,7 @@ seek_not_found:
break;
}
/* Opcode: Seek P1 P2 * * *
/* Opcode: Seek P1 P2 P3 P4 *
** Synopsis: intkey=r[P2]
**
** P1 is an open table cursor and P2 is a rowid integer. Arrange
@@ -3855,6 +3857,13 @@ seek_not_found:
** This is actually a deferred seek. Nothing actually happens until
** the cursor is used to read a record. That way, if no reads
** occur, no unnecessary I/O happens.
**
** P4 may contain an array of integers (type P4_INTARRAY) containing
** one entry for each column in the table P1 is open on. If so, then
** parameter P3 is a cursor open on a database index. If array entry
** a[i] is non-zero, then reading column (a[i]-1) from cursor P3 is
** equivalent to performing the deferred seek and then reading column i
** from P1.
*/
case OP_Seek: { /* in2 */
VdbeCursor *pC;
@@ -3869,6 +3878,9 @@ case OP_Seek: { /* in2 */
pIn2 = &aMem[pOp->p2];
pC->movetoTarget = sqlite3VdbeIntValue(pIn2);
pC->deferredMoveto = 1;
assert( pOp->p4type==P4_INTARRAY || pOp->p4.ai==0 );
pC->aAltMap = pOp->p4.ai;
pC->pAltCursor = p->apCsr[pOp->p3];
break;
}