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Overview
| Comment: | Make more aggressive use of automatic indexes when processing materalized views and subqueries. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
172f5bd27e47cbdaaab54fe4383a5ee5 |
| User & Date: | drh 2018-05-14 22:46:11.640 |
Context
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2018-05-15
| ||
| 09:09 | Fix a test case problem in wherelimit.test. (check-in: 3012df8b2c user: dan tags: trunk) | |
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2018-05-14
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| 22:46 | Make more aggressive use of automatic indexes when processing materalized views and subqueries. (check-in: 172f5bd27e user: drh tags: trunk) | |
| 15:26 | Convert the schema creation logic in the rtree extension to use the new sqlite3_str interface. (check-in: fd8b8c4196 user: drh tags: trunk) | |
Changes
Changes to src/where.c.
| ︙ | ︙ | |||
2858 2859 2860 2861 2862 2863 2864 |
pNew->nSkip = 0;
pNew->u.btree.pIndex = 0;
pNew->nLTerm = 1;
pNew->aLTerm[0] = pTerm;
/* TUNING: One-time cost for computing the automatic index is
** estimated to be X*N*log2(N) where N is the number of rows in
** the table being indexed and where X is 7 (LogEst=28) for normal
| | | | > > | 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 |
pNew->nSkip = 0;
pNew->u.btree.pIndex = 0;
pNew->nLTerm = 1;
pNew->aLTerm[0] = pTerm;
/* TUNING: One-time cost for computing the automatic index is
** estimated to be X*N*log2(N) where N is the number of rows in
** the table being indexed and where X is 7 (LogEst=28) for normal
** tables or 0.5 (LogEst=-10) for views and subqueries. The value
** of X is smaller for views and subqueries so that the query planner
** will be more aggressive about generating automatic indexes for
** those objects, since there is no opportunity to add schema
** indexes on subqueries and views. */
pNew->rSetup = rLogSize + rSize;
if( pTab->pSelect==0 && (pTab->tabFlags & TF_Ephemeral)==0 ){
pNew->rSetup += 28;
}else{
pNew->rSetup -= 10;
}
ApplyCostMultiplier(pNew->rSetup, pTab->costMult);
if( pNew->rSetup<0 ) pNew->rSetup = 0;
/* TUNING: Each index lookup yields 20 rows in the table. This
** is more than the usual guess of 10 rows, since we have no way
** of knowing how selective the index will ultimately be. It would
** not be unreasonable to make this value much larger. */
|
| ︙ | ︙ | |||
4001 4002 4003 4004 4005 4006 4007 |
LogEst rUnsorted; /* Unsorted cost of (pFrom+pWLoop) */
i8 isOrdered = pFrom->isOrdered; /* isOrdered for (pFrom+pWLoop) */
Bitmask maskNew; /* Mask of src visited by (..) */
Bitmask revMask = 0; /* Mask of rev-order loops for (..) */
if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue;
if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue;
| | | > > > | 4003 4004 4005 4006 4007 4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 |
LogEst rUnsorted; /* Unsorted cost of (pFrom+pWLoop) */
i8 isOrdered = pFrom->isOrdered; /* isOrdered for (pFrom+pWLoop) */
Bitmask maskNew; /* Mask of src visited by (..) */
Bitmask revMask = 0; /* Mask of rev-order loops for (..) */
if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue;
if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue;
if( (pWLoop->wsFlags & WHERE_AUTO_INDEX)!=0 && pFrom->nRow<3 ){
/* Do not use an automatic index if the this loop is expected
** to run less than 1.25 times. It is tempting to also exclude
** automatic index usage on an outer loop, but sometimes an automatic
** index is useful in the outer loop of a correlated subquery. */
assert( 10==sqlite3LogEst(2) );
continue;
}
/* At this point, pWLoop is a candidate to be the next loop.
** Compute its cost */
rUnsorted = sqlite3LogEstAdd(pWLoop->rSetup,pWLoop->rRun + pFrom->nRow);
rUnsorted = sqlite3LogEstAdd(rUnsorted, pFrom->rUnsorted);
nOut = pFrom->nRow + pWLoop->nOut;
maskNew = pFrom->maskLoop | pWLoop->maskSelf;
if( isOrdered<0 ){
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| ︙ | ︙ |