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Merge the implementation of OP_IdxRowid and OP_Seek so that OP_Seek no longer

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requires the rowid register and a separate OP_IdxRowid call.  Shorter and
faster prepared statements result.

FossilOrigin-Name: 9bec50a1e7796a6e038db9b1cc7cc1e7e350bf74
This commit is contained in:
drh
2016-01-30 16:59:56 +00:00
parent b8d66dc4ec
commit 784c1b93fb
4 changed files with 66 additions and 65 deletions
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103
src/vdbe.c
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@@ -3857,42 +3857,6 @@ seek_not_found:
}
break;
}
/* Opcode: Seek P1 P2 P3 P4 *
** Synopsis: intkey=r[P2]
**
** P1 is an open table cursor and P2 is a rowid integer. Arrange
** for P1 to move so that it points to the rowid given by P2.
**
** 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;
assert( pOp->p1>=0 && pOp->p1<p->nCursor );
pC = p->apCsr[pOp->p1];
assert( pC!=0 );
assert( pC->eCurType==CURTYPE_BTREE );
assert( pC->uc.pCursor!=0 );
assert( pC->isTable );
pC->nullRow = 0;
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;
}
/* Opcode: Found P1 P2 P3 P4 *
@@ -4987,6 +4951,25 @@ case OP_IdxDelete: {
break;
}
/* Opcode: Seek P1 * P3 P4 *
** Synopsis: Move P3 to P1.rowid
**
** P1 is an open index cursor and P3 is a cursor on the corresponding
** table. This opcode does a deferred seek of the P3 table cursor
** to the row that corresponds to the current row of P1.
**
** This is 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 be an array of integers (type P4_INTARRAY) containing
** one entry for each column in the P3 table. 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. This information is stored in P3 and used to redirect
** reads against P3 over to P1, thus possibly avoiding the need to
** seek and read cursor P3.
*/
/* Opcode: IdxRowid P1 P2 * * *
** Synopsis: r[P2]=rowid
**
@@ -4996,37 +4979,57 @@ case OP_IdxDelete: {
**
** See also: Rowid, MakeRecord.
*/
case OP_Seek:
case OP_IdxRowid: { /* out2 */
BtCursor *pCrsr;
VdbeCursor *pC;
i64 rowid;
VdbeCursor *pC; /* The P1 index cursor */
VdbeCursor *pTabCur; /* The P2 table cursor (OP_Seek only) */
i64 rowid; /* Rowid that P1 current points to */
pOut = out2Prerelease(p, pOp);
assert( pOp->p1>=0 && pOp->p1<p->nCursor );
pC = p->apCsr[pOp->p1];
assert( pC!=0 );
assert( pC->eCurType==CURTYPE_BTREE );
pCrsr = pC->uc.pCursor;
assert( pCrsr!=0 );
pOut->flags = MEM_Null;
assert( pC->uc.pCursor!=0 );
assert( pC->isTable==0 );
assert( pC->deferredMoveto==0 );
assert( !pC->nullRow || pOp->opcode==OP_IdxRowid );
/* The IdxRowid and Seek opcodes are combined because of the commonality
** of sqlite3VdbeCursorRestore() and sqlite3VdbeIdxRowid(). */
rc = sqlite3VdbeCursorRestore(pC);
/* sqlite3VbeCursorRestore() can only fail if the record has been deleted
** out from under the cursor. That will never happend for an IdxRowid
** opcode, hence the NEVER() arround the check of the return value.
*/
rc = sqlite3VdbeCursorRestore(pC);
** out from under the cursor. That will never happens for an IdxRowid
** or Seek opcode */
if( NEVER(rc!=SQLITE_OK) ) goto abort_due_to_error;
if( !pC->nullRow ){
rowid = 0; /* Not needed. Only used to silence a warning. */
rc = sqlite3VdbeIdxRowid(db, pCrsr, &rowid);
rc = sqlite3VdbeIdxRowid(db, pC->uc.pCursor, &rowid);
if( rc!=SQLITE_OK ){
goto abort_due_to_error;
}
pOut->u.i = rowid;
pOut->flags = MEM_Int;
if( pOp->opcode==OP_Seek ){
assert( pOp->p3>=0 && pOp->p3<p->nCursor );
pTabCur = p->apCsr[pOp->p3];
assert( pTabCur!=0 );
assert( pTabCur->eCurType==CURTYPE_BTREE );
assert( pTabCur->uc.pCursor!=0 );
assert( pTabCur->isTable );
pTabCur->nullRow = 0;
pTabCur->movetoTarget = rowid;
pTabCur->deferredMoveto = 1;
assert( pOp->p4type==P4_INTARRAY || pOp->p4.ai==0 );
pTabCur->aAltMap = pOp->p4.ai;
pTabCur->pAltCursor = pC;
}else{
pOut = out2Prerelease(p, pOp);
pOut->u.i = rowid;
pOut->flags = MEM_Int;
}
}else{
assert( pOp->opcode==OP_IdxRowid );
sqlite3VdbeMemSetNull(&aMem[pOp->p2]);
}
break;
}