diff options
Diffstat (limited to 'src/wherecode.c')
| -rw-r--r-- | src/wherecode.c | 77 |
1 files changed, 61 insertions, 16 deletions
diff --git a/src/wherecode.c b/src/wherecode.c index adc7d5b8e..dfe697f24 100644 --- a/src/wherecode.c +++ b/src/wherecode.c @@ -196,9 +196,6 @@ int sqlite3WhereExplainOneScan( pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr); } #endif - if( flags & WHERE_BLOOMFILTER ){ - sqlite3_str_appendf(&str, " WITH BLOOM FILTER"); - } #ifdef SQLITE_EXPLAIN_ESTIMATED_ROWS if( pLoop->nOut>=10 ){ sqlite3_str_appendf(&str, " (~%llu rows)", @@ -214,6 +211,52 @@ int sqlite3WhereExplainOneScan( } return ret; } + +/* +** Add a single OP_Explain opcode that describes a Bloom filter. +** +** Or if not processing EXPLAIN QUERY PLAN and not in a SQLITE_DEBUG and/or +** SQLITE_ENABLE_STMT_SCANSTATUS build, then OP_Explain opcodes are not +** required and this routine is a no-op. +** +** If an OP_Explain opcode is added to the VM, its address is returned. +** Otherwise, if no OP_Explain is coded, zero is returned. +*/ +int sqlite3WhereExplainBloomFilter( + const Parse *pParse, /* Parse context */ + const WhereInfo *pWInfo, /* WHERE clause */ + const WhereLevel *pLevel /* Bloom filter on this level */ +){ + int ret = 0; +#if !defined(SQLITE_DEBUG) && !defined(SQLITE_ENABLE_STMT_SCANSTATUS) + if( sqlite3ParseToplevel(pParse)->explain==2 ) +#endif + { + SrcItem *pItem = &pWInfo->pTabList->a[pLevel->iFrom]; + Vdbe *v = pParse->pVdbe; /* VM being constructed */ + sqlite3 *db = pParse->db; /* Database handle */ + char *zMsg; /* Text to add to EQP output */ + int i; /* Loop counter */ + WhereLoop *pLoop; /* The where loop */ + StrAccum str; /* EQP output string */ + char zBuf[100]; /* Initial space for EQP output string */ + + sqlite3StrAccumInit(&str, db, zBuf, sizeof(zBuf), SQLITE_MAX_LENGTH); + str.printfFlags = SQLITE_PRINTF_INTERNAL; + sqlite3_str_appendf(&str, "BLOOM FILTER ON %S(", pItem); + pLoop = pLevel->pWLoop; + for(i=pLoop->nSkip; i<pLoop->u.btree.nEq; i++){ + const char *z = pItem->pTab->aCol[i].zCnName; + if( i>pLoop->nSkip ) sqlite3_str_append(&str, " AND ", 5); + sqlite3_str_appendf(&str, "%s=?", z); + } + sqlite3_str_append(&str, ")", 1); + zMsg = sqlite3StrAccumFinish(&str); + ret = sqlite3VdbeAddOp4(v, OP_Explain, sqlite3VdbeCurrentAddr(v), + pParse->addrExplain, 0, zMsg,P4_DYNAMIC); + } + return ret; +} #endif /* SQLITE_OMIT_EXPLAIN */ #ifdef SQLITE_ENABLE_STMT_SCANSTATUS @@ -1304,14 +1347,20 @@ static void whereApplyPartialIndexConstraints( } } -#if 1 /* -** An OP_Filter has just been generated, but the corresponding -** index search has not yet been performed. This routine -** checks to see if there are additional WHERE_BLOOMFILTER in -** inner loops that can be evaluated right away, and if there are, -** it evaluates those filters as well, and removes the WHERE_BLOOMFILTER -** tag. +** This routine is called right after An OP_Filter has been generated and +** before the corresponding index search has been performed. This routine +** checks to see if there are additional Bloom filters in inner loops that +** can be checked prior to doing the index lookup. If there are available +** inner-loop Bloom filters, then evaluate those filters now, before the +** index lookup. The idea is that a Bloom filter check is way faster than +** an index lookup, and the Bloom filter might return false, meaning that +** the index lookup can be skipped. +** +** We know that an inner loop uses a Bloom filter because it has the +** WhereLevel.regFilter set. If an inner-loop Bloom filter is checked, +** then clear the WhereLoeve.regFilter value to prevent the Bloom filter +** from being checked a second time when the inner loop is evaluated. */ static SQLITE_NOINLINE void filterPullDown( Parse *pParse, /* Parsing context */ @@ -1323,9 +1372,8 @@ static SQLITE_NOINLINE void filterPullDown( while( ++iLevel < pWInfo->nLevel ){ WhereLevel *pLevel = &pWInfo->a[iLevel]; WhereLoop *pLoop = pLevel->pWLoop; - if( (pLoop->wsFlags & WHERE_BLOOMFILTER)==0 ) continue; + if( pLevel->regFilter==0 ) continue; if( pLoop->prereq & notReady ) continue; - sqlite3ConstructBloomFilter(pWInfo, &pWInfo->a[iLevel]); if( pLoop->wsFlags & WHERE_IPK ){ WhereTerm *pTerm = pLoop->aLTerm[0]; int r1, regRowid; @@ -1351,12 +1399,9 @@ static SQLITE_NOINLINE void filterPullDown( addrNxt, r1, nEq); VdbeCoverage(pParse->pVdbe); } - pLoop->wsFlags &= ~WHERE_BLOOMFILTER; + pLevel->regFilter = 0; } } -#else -#define filterPullDown(A,B,C,D,E) -#endif /* ** Generate code for the start of the iLevel-th loop in the WHERE clause |