-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
-C Add\sthe\sability\sto\suse\sindices\swhen\sa\srange\scontraint\sis\sbounded\son\nthe\slower\send\sby\sNULL.
-D 2011-01-21T14:37:04.663
+C Make\suse\sof\shistogram\sdata\sto\smake\sbetter\sestimates\sfor\sthe\snumber\sof\srows\nthat\swill\sbe\sreturned\sfrom\s"x\sIN\s(v1,v2,v3,...)"\sconstraints.
+D 2011-01-21T16:27:18.621
F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
F Makefile.in de6498556d536ae60bb8bb10e8c1ba011448658c
F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
F src/wal.c dbca424f71678f663a286ab2a98f947af1d412a7
F src/wal.h c1aac6593a0b02b15dc625987e619edeab39292e
F src/walker.c 3112bb3afe1d85dc52317cb1d752055e9a781f8f
-F src/where.c cf219a4275cf430d0e7df9d2db04e9ba29702f8e
+F src/where.c 7f2844afffd9e09373e874a74de81d3502b2a35c
F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
F test/alias.test 4529fbc152f190268a15f9384a5651bbbabc9d87
F test/all.test 51756962d522e474338e9b2ebb26e7364d4aa125
F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P c7b59afaf0c0bf85dbaf0a122cc8d65fca93680f
-R 07d2f363ee58370384294fd182ee30ff
+P f73a167b434fadcbbd15e3891c4b7f4f87f6363c
+R 46f7d508c889f9891a64638b5f1737ae
U drh
-Z 32ed47abc5f3838cb9feba0ba8b99416
+Z 14ba122ed035896c7c1b08aa324c4833
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** column of an index and sqlite_stat2 histogram data is available
** for that index.
**
-** Write the estimated row count into *pnRow. If unable to make
-** an estimate, leave *pnRow unchanged.
+** Write the estimated row count into *pnRow and return SQLITE_OK.
+** If unable to make an estimate, leave *pnRow unchanged and return
+** non-zero.
**
** This routine can fail if it is unable to load a collating sequence
** required for string comparison, or if unable to allocate memory
** for a UTF conversion required for comparison. The error is stored
** in the pParse structure.
*/
-void whereEqScanEst(
+int whereEqualScanEst(
Parse *pParse, /* Parsing & code generating context */
Index *p, /* The index whose left-most column is pTerm */
- WhereTerm *pTerm, /* The x=VALUE constraint */
+ Expr *pExpr, /* Expression for VALUE in the x=VALUE constraint */
double *pnRow /* Write the revised row estimate here */
){
sqlite3_value *pRhs = 0; /* VALUE on right-hand side of pTerm */
double nRowEst; /* New estimate of the number of rows */
assert( p->aSample!=0 );
- assert( pTerm->eOperator==WO_EQ );
aff = p->pTable->aCol[p->aiColumn[0]].affinity;
- rc = valueFromExpr(pParse, pTerm->pExpr->pRight, aff, &pRhs);
- if( rc ) goto whereEqScanEst_cancel;
+ rc = valueFromExpr(pParse, pExpr, aff, &pRhs);
+ if( rc ) goto whereEqualScanEst_cancel;
+ if( pRhs==0 ) return SQLITE_NOTFOUND;
rc = whereRangeRegion(pParse, p, pRhs, 0, &iLower);
- if( rc ) goto whereEqScanEst_cancel;
+ if( rc ) goto whereEqualScanEst_cancel;
rc = whereRangeRegion(pParse, p, pRhs, 1, &iUpper);
- if( rc ) goto whereEqScanEst_cancel;
+ if( rc ) goto whereEqualScanEst_cancel;
WHERETRACE(("equality scan regions: %d..%d\n", iLower, iUpper));
if( iLower>=iUpper ){
nRowEst = p->aiRowEst[0]/(SQLITE_INDEX_SAMPLES*2);
*pnRow = nRowEst;
}
-whereEqScanEst_cancel:
+whereEqualScanEst_cancel:
sqlite3ValueFree(pRhs);
+ return rc;
+}
+#endif /* defined(SQLITE_ENABLE_STAT2) */
+
+#ifdef SQLITE_ENABLE_STAT2
+/*
+** Estimate the number of rows that will be returned based on
+** an IN constraint "x IN (V1,V2,V3,...)" where the right-hand side
+** of the IN operator is a list of values.
+**
+** Write the estimated row count into *pnRow and return SQLITE_OK.
+** If unable to make an estimate, leave *pnRow unchanged and return
+** non-zero.
+**
+** This routine can fail if it is unable to load a collating sequence
+** required for string comparison, or if unable to allocate memory
+** for a UTF conversion required for comparison. The error is stored
+** in the pParse structure.
+*/
+int whereInScanEst(
+ Parse *pParse, /* Parsing & code generating context */
+ Index *p, /* The index whose left-most column is pTerm */
+ ExprList *pList, /* The value list on the RHS of "x IN (v1,v2,v3,...)" */
+ double *pnRow /* Write the revised row estimate here */
+){
+ sqlite3_value *pVal = 0; /* One value from list */
+ int iLower, iUpper; /* Range of histogram regions containing pRhs */
+ u8 aff; /* Column affinity */
+ int rc; /* Subfunction return code */
+ double nRowEst; /* New estimate of the number of rows */
+ int nRegion = 0; /* Number of histogram regions spanned */
+ int nSingle = 0; /* Count of values contained within one region */
+ int nNotFound = 0; /* Count of values that are not constants */
+ int i; /* Loop counter */
+ u8 aHit[SQLITE_INDEX_SAMPLES+1]; /* Histogram regions that are spanned */
+
+ assert( p->aSample!=0 );
+ aff = p->pTable->aCol[p->aiColumn[0]].affinity;
+ memset(aHit, 0, sizeof(aHit));
+ for(i=0; i<pList->nExpr; i++){
+ sqlite3ValueFree(pVal);
+ rc = valueFromExpr(pParse, pList->a[i].pExpr, aff, &pVal);
+ if( rc ) break;
+ if( pVal==0 ){
+ nNotFound++;
+ continue;
+ }
+ rc = whereRangeRegion(pParse, p, pVal, 0, &iLower);
+ if( rc ) break;
+ rc = whereRangeRegion(pParse, p, pVal, 1, &iUpper);
+ if( rc ) break;
+ if( iLower>=iUpper ){
+ nSingle++;
+ }
+ assert( iLower>=0 && iUpper<=SQLITE_INDEX_SAMPLES );
+ while( iLower<=iUpper ) aHit[iLower++] = 1;
+ }
+ if( rc==SQLITE_OK ){
+ for(i=nRegion=0; i<ArraySize(aHit); i++) nRegion += aHit[i];
+ nRowEst = nRegion*p->aiRowEst[0]/(SQLITE_INDEX_SAMPLES+1)
+ + nNotFound*p->aiRowEst[1];
+ if( nRowEst > p->aiRowEst[0] ) nRowEst = p->aiRowEst[0];
+ *pnRow = nRowEst;
+ WHERETRACE(("IN row estimate: nRegion=%d, nSingle=%d, nNotFound=%d\n",
+ nRegion, nSingle, nNotFound));
+ }
+ sqlite3ValueFree(pVal);
+ return rc;
}
#endif /* defined(SQLITE_ENABLE_STAT2) */
int bLookup = 0;
WhereTerm *pTerm; /* A single term of the WHERE clause */
#ifdef SQLITE_ENABLE_STAT2
- WhereTerm *pFirstEqTerm = 0; /* First WO_EQ term */
+ WhereTerm *pFirstTerm = 0; /* First term matching the index */
#endif
/* Determine the values of nEq and nInMul */
wsFlags |= WHERE_COLUMN_NULL;
}
#ifdef SQLITE_ENABLE_STAT2
- else if( nEq==0 && pProbe->aSample ){
- pFirstEqTerm = pTerm;
- }
+ if( nEq==0 && pProbe->aSample ) pFirstTerm = pTerm;
#endif
used |= pTerm->prereqRight;
}
** to get a better estimate on the number of rows based on
** VALUE and how common that value is according to the histogram.
*/
- if( nRow>(double)1 && nEq==1 && pFirstEqTerm!=0 ){
- whereEqScanEst(pParse, pProbe, pFirstEqTerm, &nRow);
+ if( nRow>(double)1 && nEq==1 && pFirstTerm!=0 ){
+ if( pFirstTerm->eOperator==WO_EQ ){
+ whereEqualScanEst(pParse, pProbe, pFirstTerm->pExpr->pRight, &nRow);
+ }else if( pFirstTerm->eOperator==WO_IN && bInEst==0 ){
+ whereInScanEst(pParse, pProbe, pFirstTerm->pExpr->x.pList, &nRow);
+ }
}
#endif /* SQLITE_ENABLE_STAT2 */
projects / thirdparty / sqlite.git / commitdiff
