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Overview
| Comment: | Improved WHERETRACE messages for the estimated output row reductions from range scans. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
fdd478bb11eb9e244a7a1fb628ac27c5 |
| User & Date: | drh 2014-08-28 19:38:22 |
Context
|
2014-08-29
| ||
| 14:20 | Not a fault after all, rather a testing mistake. Move this change back to trunk. Was: Avoid an unnecessary OP_Move operation for expression subqueries. (check-in: 2a74129a user: drh tags: trunk) | |
| 12:29 | Contains a fault. Was: Avoid an unnecessary OP_Move operation for expression subqueries. (Closed-Leaf check-in: 462f42af user: drh tags: mistake) | |
| 11:24 | Add the sqlite3VdbeChangeDest() routine that can be used to eliminate OP_Move opcodes. (Closed-Leaf check-in: 8c57bcc3 user: drh tags: experimental) | |
|
2014-08-28
| ||
| 19:38 | Improved WHERETRACE messages for the estimated output row reductions from range scans. (check-in: fdd478bb user: drh tags: trunk) | |
| 17:30 | Fix a problem causing an inaccurate stat4-based estimate for the number of rows visited by a range scan. (check-in: a9daf3ac user: drh tags: trunk) | |
Changes
Changes to src/where.c.
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nNew = sqlite3LogEst(iUpper - iLower);
}else{
nNew = 10; assert( 10==sqlite3LogEst(2) );
}
if( nNew<nOut ){
nOut = nNew;
}
WHERETRACE(0x10, ("range scan regions: %u..%u est=%d\n",
(u32)iLower, (u32)iUpper, nOut));
}
}else{
int bDone = 0;
rc = whereRangeSkipScanEst(pParse, pLower, pUpper, pLoop, &bDone);
if( bDone ) return rc;
}
................................................................................
** index. While a closed range (e.g. col BETWEEN ? AND ?) is estimated to
** match 1/64 of the index. */
if( pLower && pUpper ) nNew -= 20;
nOut -= (pLower!=0) + (pUpper!=0);
if( nNew<10 ) nNew = 10;
if( nNew<nOut ) nOut = nNew;
pLoop->nOut = (LogEst)nOut;
return rc;
}
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
/*
** Estimate the number of rows that will be returned based on
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nNew = sqlite3LogEst(iUpper - iLower);
}else{
nNew = 10; assert( 10==sqlite3LogEst(2) );
}
if( nNew<nOut ){
nOut = nNew;
}
WHERETRACE(0x10, ("STAT4 range scan: %u..%u est=%d\n",
(u32)iLower, (u32)iUpper, nOut));
}
}else{
int bDone = 0;
rc = whereRangeSkipScanEst(pParse, pLower, pUpper, pLoop, &bDone);
if( bDone ) return rc;
}
................................................................................
** index. While a closed range (e.g. col BETWEEN ? AND ?) is estimated to
** match 1/64 of the index. */
if( pLower && pUpper ) nNew -= 20;
nOut -= (pLower!=0) + (pUpper!=0);
if( nNew<10 ) nNew = 10;
if( nNew<nOut ) nOut = nNew;
#if defined(WHERETRACE_ENABLED)
if( pLoop->nOut>nOut ){
WHERETRACE(0x10,("Range scan lowers nOut from %d to %d\n",
pLoop->nOut, nOut));
}
#endif
pLoop->nOut = (LogEst)nOut;
return rc;
}
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
/*
** Estimate the number of rows that will be returned based on
|