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Overview
| Comment: | Honor a high likelihood() on range constraints. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
401235edf40fcd665eaf426cf5155ac6 |
| User & Date: | drh 2014-10-24 15:26:29 |
Context
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2014-10-24
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| 19:28 | Enhance the automatic index logic so that it creates a partial index when doing so gives the same answer for less work. UPDATE: This change introduced a bug described by ticket [2326c258d02ead33]. check-in: d95d0313 user: drh tags: trunk | |
| 15:26 | Honor a high likelihood() on range constraints. check-in: 401235ed user: drh tags: trunk | |
| 14:32 | Get the likelihood() functions working on operators like BETWEEN that create virtual terms in the WHERE-clause analysis. check-in: 03d0498d user: drh tags: trunk | |
Changes
Changes to src/where.c.
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UNUSED_PARAMETER(pBuilder); assert( pLower || pUpper ); #endif assert( pUpper==0 || (pUpper->wtFlags & TERM_VNULL)==0 ); nNew = whereRangeAdjust(pLower, nOut); nNew = whereRangeAdjust(pUpper, nNew); /* TUNING: If there is both an upper and lower limit, assume the range is ** reduced by an additional 75%. This means that, by default, an open-ended ** range query (e.g. col > ?) is assumed to match 1/4 of the rows in the ** 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", |
| > > | > |
2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 |
UNUSED_PARAMETER(pBuilder); assert( pLower || pUpper ); #endif assert( pUpper==0 || (pUpper->wtFlags & TERM_VNULL)==0 ); nNew = whereRangeAdjust(pLower, nOut); nNew = whereRangeAdjust(pUpper, nNew); /* TUNING: If there is both an upper and lower limit and neither limit ** has an application-defined likelihood(), assume the range is ** reduced by an additional 75%. This means that, by default, an open-ended ** range query (e.g. col > ?) is assumed to match 1/4 of the rows in the ** index. While a closed range (e.g. col BETWEEN ? AND ?) is estimated to ** match 1/64 of the index. */ if( pLower && pLower->truthProb>0 && pUpper && pUpper->truthProb>0 ){ 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", |