diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/vdbe.c | 93 | ||||
| -rw-r--r-- | src/wherecode.c | 5 |
2 files changed, 69 insertions, 29 deletions
diff --git a/src/vdbe.c b/src/vdbe.c index c2c829b1a..1797aca00 100644 --- a/src/vdbe.c +++ b/src/vdbe.c @@ -4721,7 +4721,7 @@ seek_not_found: } -/* Opcode: SeekScan P1 P2 * * * +/* Opcode: SeekScan P1 P2 * * P5 ** Synopsis: Scan-ahead up to P1 rows ** ** This opcode is a prefix opcode to OP_SeekGE. In other words, this @@ -4731,8 +4731,8 @@ seek_not_found: ** This opcode uses the P1 through P4 operands of the subsequent ** OP_SeekGE. In the text that follows, the operands of the subsequent ** OP_SeekGE opcode are denoted as SeekOP.P1 through SeekOP.P4. Only -** the P1 and P2 operands of this opcode are also used, and are called -** This.P1 and This.P2. +** the P1, P2 and P5 operands of this opcode are also used, and are called +** This.P1, This.P2 and This.P5. ** ** This opcode helps to optimize IN operators on a multi-column index ** where the IN operator is on the later terms of the index by avoiding @@ -4742,29 +4742,51 @@ seek_not_found: ** ** The SeekGE.P3 and SeekGE.P4 operands identify an unpacked key which ** is the desired entry that we want the cursor SeekGE.P1 to be pointing -** to. Call this SeekGE.P4/P5 row the "target". +** to. Call this SeekGE.P3/P4 row the "target". ** ** If the SeekGE.P1 cursor is not currently pointing to a valid row, ** then this opcode is a no-op and control passes through into the OP_SeekGE. ** ** If the SeekGE.P1 cursor is pointing to a valid row, then that row ** might be the target row, or it might be near and slightly before the -** target row. This opcode attempts to position the cursor on the target -** row by, perhaps by invoking sqlite3BtreeStep() on the cursor -** between 0 and This.P1 times. -** -** There are three possible outcomes from this opcode:<ol> -** -** <li> If after This.P1 steps, the cursor is still pointing to a place that -** is earlier in the btree than the target row, then fall through -** into the subsquence OP_SeekGE opcode. -** -** <li> If the cursor is successfully moved to the target row by 0 or more -** sqlite3BtreeNext() calls, then jump to This.P2, which will land just -** past the OP_IdxGT or OP_IdxGE opcode that follows the OP_SeekGE. -** -** <li> If the cursor ends up past the target row (indicating that the target -** row does not exist in the btree) then jump to SeekOP.P2. +** target row, or it might be after the target row. If the cursor is +** currently before the target row, then this opcode attempts to position +** the cursor on or after the target row by invoking sqlite3BtreeStep() +** on the cursor between 1 and This.P1 times. +** +** The This.P5 parameter is a flag that indicates what to do if the +** cursor ends up pointing at a valid row that is past the target +** row. If This.P5 is false (0) then a jump is made to SeekGE.P2. If +** This.P5 is true (non-zero) then a jump is made to This.P2. The P5==0 +** case occurs when there are no inequality constraints to the right of +** the IN constraing. The jump to SeekGE.P2 ends the loop. The P5!=0 case +** occurs when there are inequality constraints to the right of the IN +** operator. In that case, the This.P2 will point either directly to or +** to setup code prior to the OP_IdxGT or OP_IdxGE opcode that checks for +** loop terminate. +** +** Possible outcomes from this opcode:<ol> +** +** <li> If the cursor is initally not pointed to any valid row, then +** fall through into the subsequent OP_SeekGE opcode. +** +** <li> If the cursor is left pointing to a row that is before the target +** row, even after making as many as This.P1 calls to +** sqlite3BtreeNext(), then also fall through into OP_SeekGE. +** +** <li> If the cursor is left pointing at the target row, either because it +** was at the target row to begin with or because one or more +** sqlite3BtreeNext() calls moved the cursor to the target row, +** then jump to This.P2.., +** +** <li> If the cursor started out before the target row and a call to +** to sqlite3BtreeNext() moved the cursor off the end of the index +** (indicating that the target row definitely does not exist in the +** btree) then jump to SeekGE.P2, ending the loop. +** +** <li> If the cursor ends up on a valid row that is past the target row +** (indicating that the target row does not exist in the btree) then +** jump to SeekOP.P2 if This.P5==0 or to This.P2 if This.P5>0. ** </ol> */ case OP_SeekScan: { @@ -4775,14 +4797,25 @@ case OP_SeekScan: { assert( pOp[1].opcode==OP_SeekGE ); - /* pOp->p2 points to the first instruction past the OP_IdxGT that - ** follows the OP_SeekGE. */ + /* If pOp->p5 is clear, then pOp->p2 points to the first instruction past the + ** OP_IdxGT that follows the OP_SeekGE. Otherwise, it points to the first + ** opcode past the OP_SeekGE itself. */ assert( pOp->p2>=(int)(pOp-aOp)+2 ); - assert( aOp[pOp->p2-1].opcode==OP_IdxGT || aOp[pOp->p2-1].opcode==OP_IdxGE ); - testcase( aOp[pOp->p2-1].opcode==OP_IdxGE ); - assert( pOp[1].p1==aOp[pOp->p2-1].p1 ); - assert( pOp[1].p2==aOp[pOp->p2-1].p2 ); - assert( pOp[1].p3==aOp[pOp->p2-1].p3 ); +#ifdef SQLITE_DEBUG + if( pOp->p5==0 ){ + /* There are no inequality constraints following the IN constraint. */ + assert( pOp[1].p1==aOp[pOp->p2-1].p1 ); + assert( pOp[1].p2==aOp[pOp->p2-1].p2 ); + assert( pOp[1].p3==aOp[pOp->p2-1].p3 ); + assert( aOp[pOp->p2-1].opcode==OP_IdxGT + || aOp[pOp->p2-1].opcode==OP_IdxGE ); + testcase( aOp[pOp->p2-1].opcode==OP_IdxGE ); + }else{ + /* There are inequality constraints. */ + assert( pOp->p2==(int)(pOp-aOp)+2 ); + assert( aOp[pOp->p2-1].opcode==OP_SeekGE ); + } +#endif assert( pOp->p1>0 ); pC = p->apCsr[pOp[1].p1]; @@ -4816,8 +4849,9 @@ case OP_SeekScan: { while(1){ rc = sqlite3VdbeIdxKeyCompare(db, pC, &r, &res); if( rc ) goto abort_due_to_error; - if( res>0 ){ + if( res>0 && pOp->p5==0 ){ seekscan_search_fail: + /* Jump to SeekGE.P2, ending the loop */ #ifdef SQLITE_DEBUG if( db->flags&SQLITE_VdbeTrace ){ printf("... %d steps and then skip\n", pOp->p1 - nStep); @@ -4827,7 +4861,8 @@ case OP_SeekScan: { pOp++; goto jump_to_p2; } - if( res==0 ){ + if( res>=0 ){ + /* Jump to This.P2, bypassing the OP_SeekGE opcode */ #ifdef SQLITE_DEBUG if( db->flags&SQLITE_VdbeTrace ){ printf("... %d steps and then success\n", pOp->p1 - nStep); diff --git a/src/wherecode.c b/src/wherecode.c index 67df73c66..85d9be501 100644 --- a/src/wherecode.c +++ b/src/wherecode.c @@ -2038,6 +2038,11 @@ Bitmask sqlite3WhereCodeOneLoopStart( ** guess. */ addrSeekScan = sqlite3VdbeAddOp1(v, OP_SeekScan, (pIdx->aiRowLogEst[0]+9)/10); + if( pRangeStart ){ + sqlite3VdbeChangeP5(v, 1); + sqlite3VdbeChangeP2(v, addrSeekScan, sqlite3VdbeCurrentAddr(v)+1); + addrSeekScan = 0; + } VdbeCoverage(v); } sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint); |