Change the query planner to do a better job of estimating the number rows
selected by a BETWEEN operator using STAT4 when both upper and lower bounds are contained within the same sample. FossilOrigin-Name: 2d36be5d9a1cdd4fd2d54fc4eeece32a81cbacc1
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drh
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@ -1,5 +1,5 @@
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C Make\ssure\sthat\sNULL\sresults\sfrom\sOP_Column\sare\sfully\sand\scompletely\sNULL\nand\sdo\snot\shave\sthe\sMEM_Ephem\sbit\sset.\s\sFix\sfor\sticket\s[094d39a4c95ee4].
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D 2014-11-05T15:57:39.984
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C Change\sthe\squery\splanner\sto\sdo\sa\sbetter\sjob\sof\sestimating\sthe\snumber\srows\nselected\sby\sa\sBETWEEN\soperator\susing\sSTAT4\swhen\sboth\supper\sand\slower\sbounds\nare\scontained\swithin\sthe\ssame\ssample.
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D 2014-11-05T19:26:12.741
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F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
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F Makefile.in cf57f673d77606ab0f2d9627ca52a9ba1464146a
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F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
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@ -302,7 +302,7 @@ F src/vtab.c 2a30791bbd7926b589401bd09c3abb33de563793
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F src/wal.c 825c948066c7604a07d56e67958cdab210749016
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F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
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F src/walker.c c253b95b4ee44b21c406e2a1052636c31ea27804
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F src/where.c 240961041f35862ebcafd260587c79a1ab7347f8
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F src/where.c 2c2081c546c90227577c502765611555503ce3f7
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F src/whereInt.h d3633e9b592103241b74b0ec76185f3e5b8b62e0
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F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
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F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
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@ -321,7 +321,7 @@ F test/analyze4.test eff2df19b8dd84529966420f29ea52edc6b56213
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F test/analyze5.test 765c4e284aa69ca172772aa940946f55629bc8c4
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F test/analyze6.test f1c552ce39cca4ec922a7e4e0e5d0203d6b3281f
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F test/analyze7.test bb1409afc9e8629e414387ef048b8e0e3e0bdc4f
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F test/analyze8.test 093d15c1c888eed5034304a98c992f7360130b88
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F test/analyze8.test c05a461d0a6b05991106467d0c47480f2e709c82
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F test/analyze9.test 72795c8113604b5dcd47a1498a61d6d7fb5d041a
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F test/analyzeA.test 3335697f6700c7052295cfd0067fc5b2aacddf9a
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F test/analyzeB.test 8bf35ee0a548aea831bf56762cb8e7fdb1db083d
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@ -1211,7 +1211,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
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F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
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F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
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F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
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P 948d6e5d07bc14b6de32ec2144c716a5532f894c
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R 4628888308aa60120db393287d665a20
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P 42705fd7d892c4fdfb95fbbb468c99569beece25
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R b31ea7cd782cb3cc21bda8e8c039f16c
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U drh
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Z e07070b00a71f6116b6f23e15e08fb5e
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Z 7c6a788d1b7b1ae57295ef90b3d9da88
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@ -1 +1 @@
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42705fd7d892c4fdfb95fbbb468c99569beece25
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2d36be5d9a1cdd4fd2d54fc4eeece32a81cbacc1
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34
src/where.c
34
src/where.c
@ -1897,7 +1897,6 @@ static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite3_index_info *p){
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}
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#endif /* !defined(SQLITE_OMIT_VIRTUALTABLE) */
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#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
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/*
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** Estimate the location of a particular key among all keys in an
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@ -1906,9 +1905,10 @@ static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite3_index_info *p){
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** aStat[0] Est. number of rows less than pVal
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** aStat[1] Est. number of rows equal to pVal
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**
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** Return SQLITE_OK on success.
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** Return the index of the sample that is the smallest sample that
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** is greater than or equal to pRec.
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*/
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static void whereKeyStats(
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static int whereKeyStats(
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Parse *pParse, /* Database connection */
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Index *pIdx, /* Index to consider domain of */
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UnpackedRecord *pRec, /* Vector of values to consider */
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@ -1990,6 +1990,7 @@ static void whereKeyStats(
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}
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aStat[0] = iLower + iGap;
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}
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return i;
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}
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#endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */
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@ -2140,7 +2141,7 @@ static int whereRangeSkipScanEst(
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** If either of the upper or lower bound is not present, then NULL is passed in
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** place of the corresponding WhereTerm.
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**
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** The value in (pBuilder->pNew->u.btree.nEq) is the index of the index
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** The value in (pBuilder->pNew->u.btree.nEq) is the number of the index
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** column subject to the range constraint. Or, equivalently, the number of
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** equality constraints optimized by the proposed index scan. For example,
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** assuming index p is on t1(a, b), and the SQL query is:
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@ -2156,7 +2157,7 @@ static int whereRangeSkipScanEst(
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**
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** When this function is called, *pnOut is set to the sqlite3LogEst() of the
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** number of rows that the index scan is expected to visit without
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** considering the range constraints. If nEq is 0, this is the number of
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** considering the range constraints. If nEq is 0, then *pnOut is the number of
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** rows in the index. Assuming no error occurs, *pnOut is adjusted (reduced)
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** to account for the range constraints pLower and pUpper.
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**
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@ -2180,9 +2181,7 @@ static int whereRangeScanEst(
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Index *p = pLoop->u.btree.pIndex;
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int nEq = pLoop->u.btree.nEq;
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if( p->nSample>0
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&& nEq<p->nSampleCol
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){
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if( p->nSample>0 && nEq<p->nSampleCol ){
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if( nEq==pBuilder->nRecValid ){
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UnpackedRecord *pRec = pBuilder->pRec;
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tRowcnt a[2];
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@ -2198,15 +2197,19 @@ static int whereRangeScanEst(
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** is not a simple variable or literal value), the lower bound of the
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** range is $P. Due to a quirk in the way whereKeyStats() works, even
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** if $L is available, whereKeyStats() is called for both ($P) and
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** ($P:$L) and the larger of the two returned values used.
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** ($P:$L) and the larger of the two returned values is used.
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**
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** Similarly, iUpper is to be set to the estimate of the number of rows
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** less than the upper bound of the range query. Where the upper bound
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** is either ($P) or ($P:$U). Again, even if $U is available, both values
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** of iUpper are requested of whereKeyStats() and the smaller used.
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**
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** The number of rows between the two bounds is then just iUpper-iLower.
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*/
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tRowcnt iLower;
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tRowcnt iUpper;
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tRowcnt iLower; /* Rows less than the lower bound */
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tRowcnt iUpper; /* Rows less than the upper bound */
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int iLwrIdx = -2; /* aSample[] for the lower bound */
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int iUprIdx = -1; /* aSample[] for the upper bound */
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if( pRec ){
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testcase( pRec->nField!=pBuilder->nRecValid );
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@ -2244,7 +2247,7 @@ static int whereRangeScanEst(
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rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq, &bOk);
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if( rc==SQLITE_OK && bOk ){
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tRowcnt iNew;
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whereKeyStats(pParse, p, pRec, 0, a);
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iLwrIdx = whereKeyStats(pParse, p, pRec, 0, a);
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iNew = a[0] + ((pLower->eOperator & (WO_GT|WO_LE)) ? a[1] : 0);
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if( iNew>iLower ) iLower = iNew;
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nOut--;
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@ -2259,7 +2262,7 @@ static int whereRangeScanEst(
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rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq, &bOk);
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if( rc==SQLITE_OK && bOk ){
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tRowcnt iNew;
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whereKeyStats(pParse, p, pRec, 1, a);
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iUprIdx = whereKeyStats(pParse, p, pRec, 1, a);
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iNew = a[0] + ((pUpper->eOperator & (WO_GT|WO_LE)) ? a[1] : 0);
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if( iNew<iUpper ) iUpper = iNew;
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nOut--;
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@ -2271,6 +2274,11 @@ static int whereRangeScanEst(
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if( rc==SQLITE_OK ){
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if( iUpper>iLower ){
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nNew = sqlite3LogEst(iUpper - iLower);
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/* TUNING: If both iUpper and iLower are derived from the same
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** sample, then assume they are 4x more selective. This brings
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** the estimated selectivity more in line with what it would be
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** if estimated without the use of STAT3/4 tables. */
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if( iLwrIdx==iUprIdx ) nNew -= 20; assert( 20==sqlite3LogEst(4) );
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}else{
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nNew = 10; assert( 10==sqlite3LogEst(2) );
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}
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@ -86,23 +86,23 @@ do_test 2.1 {
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# range.
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#
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# Test 3.2 is a little unstable. It depends on the planner estimating
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# that (b BETWEEN 50 AND 54) will match more rows than (c BETWEEN
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# that (b BETWEEN 30 AND 34) will match more rows than (c BETWEEN
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# 800000 AND 900000). Which is a pretty close call (50 vs. 32), so
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# the planner could get it wrong with an unlucky set of samples. This
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# case happens to work, but others ("b BETWEEN 40 AND 44" for example)
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# will fail.
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#
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do_execsql_test 3.0 {
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SELECT count(*) FROM t1 WHERE b BETWEEN 50 AND 54;
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SELECT count(*) FROM t1 WHERE b BETWEEN 30 AND 34;
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SELECT count(*) FROM t1 WHERE c BETWEEN 0 AND 100000;
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SELECT count(*) FROM t1 WHERE c BETWEEN 800000 AND 900000;
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} {50 376 32}
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do_test 3.1 {
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eqp {SELECT * FROM t1 WHERE b BETWEEN 50 AND 54 AND c BETWEEN 0 AND 100000}
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eqp {SELECT * FROM t1 WHERE b BETWEEN 30 AND 34 AND c BETWEEN 0 AND 100000}
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} {0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b>? AND b<?)}}
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do_test 3.2 {
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eqp {SELECT * FROM t1
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WHERE b BETWEEN 50 AND 54 AND c BETWEEN 800000 AND 900000}
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WHERE b BETWEEN 30 AND 34 AND c BETWEEN 800000 AND 900000}
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} {0 0 0 {SEARCH TABLE t1 USING INDEX t1c (c>? AND c<?)}}
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do_test 3.3 {
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eqp {SELECT * FROM t1 WHERE a=100 AND c BETWEEN 0 AND 100000}
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