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Overview
| Comment: | When running ANALYZE, it is not necessary to check the right-most key column for changes since that column will always change if none of the previous columns have. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
48f40861db4fbd10725a2b8b606d44fe |
| User & Date: | drh 2014-07-22 22:46:54 |
Context
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2014-07-23
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| 15:51 | Updated documentation on sqlite3_temp_directory. No changes to code. (check-in: e6225a7b user: drh tags: trunk) | |
| 01:26 | Add support for parsing C-style hexadecimal literals. (check-in: 34a1f38b user: drh tags: hex-literal) | |
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2014-07-22
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| 22:46 | When running ANALYZE, it is not necessary to check the right-most key column for changes since that column will always change if none of the previous columns have. (check-in: 48f40861 user: drh tags: trunk) | |
| 20:02 | Add the OP_ReopenIdx opcode that works like OP_OpenRead except that it becomes a no-op if the cursor is already open on the same index. Update the OR-optimization logic to make use of OP_ReopenIdx in order to avoid unnecessary cursor open requests sent to the B-Tree layer. (check-in: 77f412ca user: drh tags: trunk) | |
Changes
Changes to src/analyze.c.
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** regChng = 1
** if( idx(1) != regPrev(1) ) goto chng_addr_1
** ...
** regChng = N
** goto chng_addr_N
*/
addrNextRow = sqlite3VdbeCurrentAddr(v);
for(i=0; i<nCol; i++){
char *pColl = (char*)sqlite3LocateCollSeq(pParse, pIdx->azColl[i]);
sqlite3VdbeAddOp2(v, OP_Integer, i, regChng);
sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regTemp);
aGotoChng[i] =
sqlite3VdbeAddOp4(v, OP_Ne, regTemp, 0, regPrev+i, pColl, P4_COLLSEQ);
sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
VdbeCoverage(v);
}
sqlite3VdbeAddOp2(v, OP_Integer, nCol, regChng);
aGotoChng[nCol] = sqlite3VdbeAddOp0(v, OP_Goto);
/*
** chng_addr_0:
** regPrev(0) = idx(0)
** chng_addr_1:
** regPrev(1) = idx(1)
** ...
*/
sqlite3VdbeJumpHere(v, addrGotoChng0);
for(i=0; i<nCol; i++){
sqlite3VdbeJumpHere(v, aGotoChng[i]);
sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regPrev+i);
}
/*
** chng_addr_N:
** regRowid = idx(rowid) // STAT34 only
|
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** regChng = 1
** if( idx(1) != regPrev(1) ) goto chng_addr_1
** ...
** regChng = N
** goto chng_addr_N
*/
addrNextRow = sqlite3VdbeCurrentAddr(v);
for(i=0; i<nCol-1; i++){
char *pColl = (char*)sqlite3LocateCollSeq(pParse, pIdx->azColl[i]);
sqlite3VdbeAddOp2(v, OP_Integer, i, regChng);
sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regTemp);
aGotoChng[i] =
sqlite3VdbeAddOp4(v, OP_Ne, regTemp, 0, regPrev+i, pColl, P4_COLLSEQ);
sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
VdbeCoverage(v);
}
sqlite3VdbeAddOp2(v, OP_Integer, nCol-1, regChng);
aGotoChng[nCol] = sqlite3VdbeAddOp0(v, OP_Goto);
/*
** chng_addr_0:
** regPrev(0) = idx(0)
** chng_addr_1:
** regPrev(1) = idx(1)
** ...
*/
sqlite3VdbeJumpHere(v, addrGotoChng0);
for(i=0; i<nCol-1; i++){
sqlite3VdbeJumpHere(v, aGotoChng[i]);
sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regPrev+i);
}
/*
** chng_addr_N:
** regRowid = idx(rowid) // STAT34 only
|