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Add a new OP_SeekRowid opcode, that combines the functions of OP_MustBeInt

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and OP_NotExists.  This makes the code slightly smaller and faster.

FossilOrigin-Name: ffe80a1bfa014943a614fc6993c1749b9bfec4c1
This commit is contained in:
drh
2016-05-26 20:56:38 +00:00
parent ce3c5011d9
commit eeb9565a3e
6 changed files with 57 additions and 23 deletions
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50
src/vdbe.c
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@@ -4023,6 +4023,30 @@ case OP_Found: { /* jump, in3 */
break;
}
/* Opcode: SeekRowid P1 P2 P3 * *
** Synopsis: intkey=r[P3]
**
** P1 is the index of a cursor open on an SQL table btree (with integer
** keys). If register P3 does not contain an integer or if P1 does not
** contain a record with rowid P3 then jump immediately to P2.
** Or, if P2 is 0, raise an SQLITE_CORRUPT error. If P1 does contain
** a record with rowid P3 then
** leave the cursor pointing at that record and fall through to the next
** instruction.
**
** The OP_NotExists opcode performs the same operation, but with OP_NotExists
** the P3 register must be guaranteed to contain an integer value. With this
** opcode, register P3 might not contain an integer.
**
** The OP_NotFound opcode performs the same operation on index btrees
** (with arbitrary multi-value keys).
**
** This opcode leaves the cursor in a state where it cannot be advanced
** in either direction. In other words, the Next and Prev opcodes will
** not work following this opcode.
**
** See also: Found, NotFound, NoConflict, SeekRowid
*/
/* Opcode: NotExists P1 P2 P3 * *
** Synopsis: intkey=r[P3]
**
@@ -4033,6 +4057,10 @@ case OP_Found: { /* jump, in3 */
** leave the cursor pointing at that record and fall through to the next
** instruction.
**
** The OP_SeekRowid opcode performs the same operation but also allows the
** P3 register to contain a non-integer value, in which case the jump is
** always taken. This opcode requires that P3 always contain an integer.
**
** The OP_NotFound opcode performs the same operation on index btrees
** (with arbitrary multi-value keys).
**
@@ -4040,14 +4068,21 @@ case OP_Found: { /* jump, in3 */
** in either direction. In other words, the Next and Prev opcodes will
** not work following this opcode.
**
** See also: Found, NotFound, NoConflict
** See also: Found, NotFound, NoConflict, SeekRowid
*/
case OP_NotExists: { /* jump, in3 */
case OP_SeekRowid: { /* jump, in3 */
VdbeCursor *pC;
BtCursor *pCrsr;
int res;
u64 iKey;
pIn3 = &aMem[pOp->p3];
if( (pIn3->flags & MEM_Int)==0 ){
applyAffinity(pIn3, SQLITE_AFF_NUMERIC, encoding);
if( (pIn3->flags & MEM_Int)==0 ) goto jump_to_p2;
}
/* Fall through into OP_NotExists */
case OP_NotExists: /* jump, in3 */
pIn3 = &aMem[pOp->p3];
assert( pIn3->flags & MEM_Int );
assert( pOp->p1>=0 && pOp->p1<p->nCursor );
@@ -4250,10 +4285,12 @@ case OP_NewRowid: { /* out2 */
** sqlite3_last_insert_rowid() function (otherwise it is unmodified).
**
** If the OPFLAG_USESEEKRESULT flag of P5 is set and if the result of
** the last seek operation (OP_NotExists) was a success, then this
** the last seek operation (OP_NotExists or OP_SeekRowid) was a success,
** then this
** operation will not attempt to find the appropriate row before doing
** the insert but will instead overwrite the row that the cursor is
** currently pointing to. Presumably, the prior OP_NotExists opcode
** currently pointing to. Presumably, the prior OP_NotExists or
** OP_SeekRowid opcode
** has already positioned the cursor correctly. This is an optimization
** that boosts performance by avoiding redundant seeks.
**
@@ -4611,8 +4648,9 @@ case OP_RowData: {
pCrsr = pC->uc.pCursor;
/* The OP_RowKey and OP_RowData opcodes always follow OP_NotExists or
** OP_Rewind/Op_Next with no intervening instructions that might invalidate
** the cursor. If this where not the case, on of the following assert()s
** OP_SeekRowid or OP_Rewind/Op_Next with no intervening instructions
** that might invalidate the cursor.
** If this where not the case, on of the following assert()s
** would fail. Should this ever change (because of changes in the code
** generator) then the fix would be to insert a call to
** sqlite3VdbeCursorMoveto().