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Overview
| Comment: | Replace the OP_SetIfNotPos operator with OP_OffsetLimit in the VDBE, for simpler and smaller code. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
7ac017a498b6fb28343eef2d24e400c7 |
| User & Date: | drh 2016-01-25 15:57:29.060 |
Context
|
2016-01-25
| ||
| 22:08 | Fix a compiler warning about doing pointer arithmetic involving a NULL pointer even though the result of computation is never used. (check-in: 7c49a9478b user: drh tags: trunk) | |
| 17:04 | Fix issues on unix with opening database files via symlinks that are not in the current working directory. And with nested symlinks. (check-in: 80398fd44f user: dan tags: follow-symlinks) | |
| 15:57 | Replace the OP_SetIfNotPos operator with OP_OffsetLimit in the VDBE, for simpler and smaller code. (check-in: 7ac017a498 user: drh tags: trunk) | |
| 13:55 | Add the SQLITE_EXTRA_DURABLE compile-time option. (check-in: 30671345b1 user: drh tags: trunk) | |
Changes
Changes to src/select.c.
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}
if( p->pOffset ){
p->iOffset = iOffset = ++pParse->nMem;
pParse->nMem++; /* Allocate an extra register for limit+offset */
sqlite3ExprCode(pParse, p->pOffset, iOffset);
sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset); VdbeCoverage(v);
VdbeComment((v, "OFFSET counter"));
| | < < | 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 |
}
if( p->pOffset ){
p->iOffset = iOffset = ++pParse->nMem;
pParse->nMem++; /* Allocate an extra register for limit+offset */
sqlite3ExprCode(pParse, p->pOffset, iOffset);
sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset); VdbeCoverage(v);
VdbeComment((v, "OFFSET counter"));
sqlite3VdbeAddOp3(v, OP_OffsetLimit, iLimit, iOffset+1, iOffset);
VdbeComment((v, "LIMIT+OFFSET"));
}
}
}
#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** Return the appropriate collating sequence for the iCol-th column of
|
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p->pPrior = 0;
p->iLimit = pPrior->iLimit;
p->iOffset = pPrior->iOffset;
if( p->iLimit ){
addr = sqlite3VdbeAddOp1(v, OP_IfNot, p->iLimit); VdbeCoverage(v);
VdbeComment((v, "Jump ahead if LIMIT reached"));
if( p->iOffset ){
| | < | | 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 |
p->pPrior = 0;
p->iLimit = pPrior->iLimit;
p->iOffset = pPrior->iOffset;
if( p->iLimit ){
addr = sqlite3VdbeAddOp1(v, OP_IfNot, p->iLimit); VdbeCoverage(v);
VdbeComment((v, "Jump ahead if LIMIT reached"));
if( p->iOffset ){
sqlite3VdbeAddOp3(v, OP_OffsetLimit,
p->iLimit, p->iOffset+1, p->iOffset);
}
}
explainSetInteger(iSub2, pParse->iNextSelectId);
rc = sqlite3Select(pParse, p, &dest);
testcase( rc!=SQLITE_OK );
pDelete = p->pPrior;
p->pPrior = pPrior;
|
| ︙ | ︙ |
Changes to src/vdbe.c.
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if( pIn1->u.i>0 ){
pIn1->u.i -= pOp->p3;
goto jump_to_p2;
}
break;
}
| | | | > > > | > > > | > > > > > | < | | > > | < | 5753 5754 5755 5756 5757 5758 5759 5760 5761 5762 5763 5764 5765 5766 5767 5768 5769 5770 5771 5772 5773 5774 5775 5776 5777 5778 5779 5780 5781 5782 5783 5784 5785 5786 5787 5788 5789 5790 5791 |
if( pIn1->u.i>0 ){
pIn1->u.i -= pOp->p3;
goto jump_to_p2;
}
break;
}
/* Opcode: OffsetLimit P1 P2 P3 * *
** Synopsis: if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1)
**
** This opcode performs a commonly used computation associated with
** LIMIT and OFFSET process. r[P1] holds the limit counter. r[P3]
** holds the offset counter. The opcode computes the combined value
** of the LIMIT and OFFSET and stores that value in r[P2]. The r[P2]
** value computed is the total number of rows that will need to be
** visited in order to complete the query.
**
** If r[P3] is zero or negative, that means there is no OFFSET
** and r[P2] is set to be the value of the LIMIT, r[P1].
**
** if r[P1] is zero or negative, that means there is no LIMIT
** and r[P2] is set to -1.
**
** Otherwise, r[P2] is set to the sum of r[P1] and r[P3].
*/
case OP_OffsetLimit: { /* in1, out2, in3 */
pIn1 = &aMem[pOp->p1];
pIn3 = &aMem[pOp->p3];
pOut = out2Prerelease(p, pOp);
assert( pIn1->flags & MEM_Int );
assert( pIn3->flags & MEM_Int );
pOut->u.i = pIn1->u.i<=0 ? -1 : pIn1->u.i+(pIn3->u.i>0?pIn3->u.i:0);
break;
}
/* Opcode: IfNotZero P1 P2 P3 * *
** Synopsis: if r[P1]!=0 then r[P1]-=P3, goto P2
**
** Register P1 must contain an integer. If the content of register P1 is
|
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