Run as many Bloom filters as possible before index lookups.

FossilOrigin-Name: 06f6fefd67086896bc49272c6319545ff6c6792f18babe23aced27b60b032119

4 files changed, 149 insertions, 67 deletions

diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index e96947e81..896b2aa42 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1762,6 +1762,7 @@ struct sqlite3 {
 #define SQLITE_OmitOrderBy    0x00040000 /* Omit pointless ORDER BY */
    /* TH3 expects this value  ^^^^^^^^^^ to be 0x40000. Coordinate any change */
 #define SQLITE_BloomFilter    0x00080000 /* Use a Bloom filter on searches */
+#define SQLITE_BloomPulldown  0x00100000 /* Run Bloom filters early */
 #define SQLITE_AllOpts        0xffffffff /* All optimizations */
 
 /*
diff --git a/src/where.c b/src/where.c
index 2f7eb0609..1d88c3ed3 100644
--- a/src/where.c
+++ b/src/where.c
@@ -966,61 +966,92 @@ end_auto_index_create:
 #endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
 
 /*
-** Create a Bloom filter for the WhereLevel in the parameter.
+** Generate bytecode that will initialize a Bloom filter that is appropriate
+** for pLevel.
+**
+** If there are inner loops within pLevel that have the WHERE_BLOOMFILTER
+** flag set, initialize a Bloomfilter for them as well.  Except don't do
+** this recursive initialization if the SQLITE_BloomPulldown optimization has
+** been turned off.
+**
+** When the Bloom filter is initialized, the WHERE_BLOOMFILTER flag is cleared
+** from the loop, but the regFilter value is set to a register that implements
+** the Bloom filter.  When regFilter is positive, the
+** sqlite3WhereCodeOneLoopStart() will generate code to test the Bloom filter
+** and skip the subsequence B-Tree seek if the Bloom filter indicates that
+** no matching rows exist.
+**
+** This routine may only be called if it has previously been determined that
+** the loop would benefit from a Bloom filter, and the WHERE_BLOOMFILTER bit
+** is set.
 */
-SQLITE_NOINLINE void sqlite3ConstructBloomFilter(
-  const WhereInfo *pWInfo,    /* The WHERE clause */
-  WhereLevel *pLevel          /* Make a Bloom filter for this FROM term */
+static SQLITE_NOINLINE void constructBloomFilter(
+  WhereInfo *pWInfo,    /* The WHERE clause */
+  int iLevel,           /* Index in pWInfo->a[] that is pLevel */
+  WhereLevel *pLevel    /* Make a Bloom filter for this FROM term */
 ){
-  int addrTop;
-  int addrCont;
-  const WhereTerm *pTerm;
-  const WhereTerm *pWCEnd;
-  Parse *pParse = pWInfo->pParse;
-  Vdbe *v = pParse->pVdbe;
-  const WhereLoop *pLoop = pLevel->pWLoop;
-  int iCur;
-  
+  int addrOnce;                        /* Address of opening OP_Once */
+  int addrTop;                         /* Address of OP_Rewind */
+  int addrCont;                        /* Jump here to skip a row */
+  const WhereTerm *pTerm;              /* For looping over WHERE clause terms */
+  const WhereTerm *pWCEnd;             /* Last WHERE clause term */
+  Parse *pParse = pWInfo->pParse;      /* Parsing context */
+  Vdbe *v = pParse->pVdbe;             /* VDBE under construction */
+  WhereLoop *pLoop = pLevel->pWLoop;   /* The loop being coded */
+  int iCur;                            /* Cursor for table getting the filter */
 
   assert( pLoop!=0 );
   assert( v!=0 );
-  iCur = pLevel->iTabCur;
-  addrCont = sqlite3VdbeMakeLabel(pParse);
-  addrTop = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
-  pLevel->regFilter = ++pParse->nMem;
-  sqlite3VdbeAddOp1(v, OP_FilterInit, pLevel->regFilter);
-  sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
-  pWCEnd = &pWInfo->sWC.a[pWInfo->sWC.nTerm];
-  for(pTerm=pWInfo->sWC.a; pTerm<pWCEnd; pTerm++){
-    Expr *pExpr = pTerm->pExpr;
-    if( (pTerm->wtFlags & TERM_VIRTUAL)==0
-     && sqlite3ExprIsTableConstant(pExpr, iCur)
-    ){
-      sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL);
+  assert( pLoop->wsFlags & WHERE_BLOOMFILTER );
+
+  addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+  do{
+    sqlite3WhereExplainBloomFilter(pParse, pWInfo, pLevel);
+    addrCont = sqlite3VdbeMakeLabel(pParse);
+    iCur = pLevel->iTabCur;
+    pLevel->regFilter = ++pParse->nMem;
+    sqlite3VdbeAddOp1(v, OP_FilterInit, pLevel->regFilter);
+    addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
+    pWCEnd = &pWInfo->sWC.a[pWInfo->sWC.nTerm];
+    for(pTerm=pWInfo->sWC.a; pTerm<pWCEnd; pTerm++){
+      Expr *pExpr = pTerm->pExpr;
+      if( (pTerm->wtFlags & TERM_VIRTUAL)==0
+       && sqlite3ExprIsTableConstant(pExpr, iCur)
+      ){
+        sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL);
+      }
     }
-  }
-  if( pLoop->wsFlags & WHERE_IPK ){
-    int r1 = sqlite3GetTempReg(pParse);
-    sqlite3VdbeAddOp2(v, OP_Rowid, iCur, r1);
-    sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, 1);
-    sqlite3ReleaseTempReg(pParse, r1);
-  }else{
-    Index *pIdx = pLoop->u.btree.pIndex;
-    int n = pLoop->u.btree.nEq;
-    int r1 = sqlite3GetTempRange(pParse, n);
-    int jj;
-    for(jj=0; jj<n; jj++){
-      int iCol = pIdx->aiColumn[jj];
-      sqlite3ExprCodeGetColumnOfTable(v, pIdx->pTable, iCur, iCol,r1+jj);
-    }
-    sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, n);
-    sqlite3ReleaseTempRange(pParse, r1, n);
-  }
-  sqlite3VdbeResolveLabel(v, addrCont);
-  sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+3);
-  VdbeCoverage(v);
-  sqlite3VdbeJumpHere(v, addrTop);
-  sqlite3VdbeJumpHere(v, addrTop+2);
+    if( pLoop->wsFlags & WHERE_IPK ){
+      int r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, r1);
+      sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, 1);
+      sqlite3ReleaseTempReg(pParse, r1);
+    }else{
+      Index *pIdx = pLoop->u.btree.pIndex;
+      int n = pLoop->u.btree.nEq;
+      int r1 = sqlite3GetTempRange(pParse, n);
+      int jj;
+      for(jj=0; jj<n; jj++){
+        int iCol = pIdx->aiColumn[jj];
+        sqlite3ExprCodeGetColumnOfTable(v, pIdx->pTable, iCur, iCol,r1+jj);
+      }
+      sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, n);
+      sqlite3ReleaseTempRange(pParse, r1, n);
+    }
+    sqlite3VdbeResolveLabel(v, addrCont);
+    sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1);
+    VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addrTop);
+    pLoop->wsFlags &= ~WHERE_BLOOMFILTER;
+    if( OptimizationDisabled(pParse->db, SQLITE_BloomPulldown) ) break;
+    while( iLevel < pWInfo->nLevel ){
+      iLevel++;
+      pLevel = &pWInfo->a[iLevel];
+      pLoop = pLevel->pWLoop;
+      if( pLoop && pLoop->wsFlags & WHERE_BLOOMFILTER ) break;
+    }
+  }while( iLevel < pWInfo->nLevel );
+  sqlite3VdbeJumpHere(v, addrOnce);
 }
 
 
@@ -5535,7 +5566,7 @@ WhereInfo *sqlite3WhereBegin(
                   &pTabList->a[pLevel->iFrom], notReady, pLevel);
 #endif
       }else{
-        sqlite3ConstructBloomFilter(pWInfo, pLevel);
+        constructBloomFilter(pWInfo, ii, pLevel);
       }
       if( db->mallocFailed ) goto whereBeginError;
     }
diff --git a/src/whereInt.h b/src/whereInt.h
index 19261ca39..4da6015f1 100644
--- a/src/whereInt.h
+++ b/src/whereInt.h
@@ -484,7 +484,6 @@ struct WhereInfo {
 ** where.c:
 */
 Bitmask sqlite3WhereGetMask(WhereMaskSet*,int);
-void sqlite3ConstructBloomFilter(const WhereInfo*, WhereLevel*);
 #ifdef WHERETRACE_ENABLED
 void sqlite3WhereClausePrint(WhereClause *pWC);
 void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm);
@@ -507,8 +506,14 @@ int sqlite3WhereExplainOneScan(
   WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
   u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
 );
+int sqlite3WhereExplainBloomFilter(
+  const Parse *pParse,            /* Parse context */
+  const WhereInfo *pWInfo,        /* WHERE clause */
+  const WhereLevel *pLevel        /* Bloom filter on this level */
+);
 #else
 # define sqlite3WhereExplainOneScan(u,v,w,x) 0
+# define sqlite3WhereExplainBloomFilter(u,v,w) 0
 #endif /* SQLITE_OMIT_EXPLAIN */
 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS
 void sqlite3WhereAddScanStatus(
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