Merge trunk enhancements into the right-join branch.

FossilOrigin-Name: 3fd9706bba4a71cb5c7ce1341c3be0a7727941445820a073e7b2f0f32512e8ef

6 files changed, 65 insertions, 24 deletions

diff --git a/src/analyze.c b/src/analyze.c
index e8699653f..39009899a 100644
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -847,9 +847,14 @@ static void statGet(
     **   * "WHERE a=? AND b=?" matches 2 rows.
     **
     ** If D is the count of distinct values and K is the total number of 
-    ** rows, then each estimate is computed as:
+    ** rows, then each estimate is usually computed as:
     **
     **        I = (K+D-1)/D
+    **
+    ** In other words, I is K/D rounded up to the next whole integer.
+    ** However, if I is between 1.0 and 1.1 (in other words if I is
+    ** close to 1.0 but just a little larger) then do not round up but
+    ** instead keep the I value at 1.0.
     */
     sqlite3_str sStat;   /* Text of the constructed "stat" line */
     int i;               /* Loop counter */
@@ -860,6 +865,7 @@ static void statGet(
     for(i=0; i<p->nKeyCol; i++){
       u64 nDistinct = p->current.anDLt[i] + 1;
       u64 iVal = (p->nRow + nDistinct - 1) / nDistinct;
+      if( iVal==2 && p->nRow*10 <= nDistinct*11 ) iVal = 1;
       sqlite3_str_appendf(&sStat, " %llu", iVal);
       assert( p->current.anEq[i] );
     }
diff --git a/src/build.c b/src/build.c
index 8ae263fc3..fbd633209 100644
--- a/src/build.c
+++ b/src/build.c
@@ -172,9 +172,7 @@ void sqlite3FinishCoding(Parse *pParse){
       int i;
       int reg;
 
-      if( NEVER(pReturning->nRetCol==0) ){
-        assert( CORRUPT_DB );
-      }else{
+      if( pReturning->nRetCol ){
         sqlite3VdbeAddOp0(v, OP_FkCheck);
         addrRewind =
            sqlite3VdbeAddOp1(v, OP_Rewind, pReturning->iRetCur);
@@ -270,9 +268,7 @@ void sqlite3FinishCoding(Parse *pParse){
 
       if( pParse->bReturning ){
         Returning *pRet = pParse->u1.pReturning;
-        if( NEVER(pRet->nRetCol==0) ){
-          assert( CORRUPT_DB );
-        }else{
+        if( pRet->nRetCol ){
           sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRet->iRetCur, pRet->nRetCol);
         }
       }
@@ -3059,7 +3055,6 @@ int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
   Table *pSelTab;   /* A fake table from which we get the result set */
   Select *pSel;     /* Copy of the SELECT that implements the view */
   int nErr = 0;     /* Number of errors encountered */
-  int n;            /* Temporarily holds the number of cursors assigned */
   sqlite3 *db = pParse->db;  /* Database connection for malloc errors */
 #ifndef SQLITE_OMIT_VIRTUALTABLE
   int rc;
@@ -3117,8 +3112,9 @@ int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
   pSel = sqlite3SelectDup(db, pTable->u.view.pSelect, 0);
   if( pSel ){
     u8 eParseMode = pParse->eParseMode;
+    int nTab = pParse->nTab;
+    int nSelect = pParse->nSelect;
     pParse->eParseMode = PARSE_MODE_NORMAL;
-    n = pParse->nTab;
     sqlite3SrcListAssignCursors(pParse, pSel->pSrc);
     pTable->nCol = -1;
     DisableLookaside;
@@ -3130,7 +3126,8 @@ int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
 #else
     pSelTab = sqlite3ResultSetOfSelect(pParse, pSel, SQLITE_AFF_NONE);
 #endif
-    pParse->nTab = n;
+    pParse->nTab = nTab;
+    pParse->nSelect = nSelect;
     if( pSelTab==0 ){
       pTable->nCol = 0;
       nErr++;
diff --git a/src/expr.c b/src/expr.c
index f532bba2e..2bc5eae20 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -2297,6 +2297,42 @@ int sqlite3ExprIsTableConstant(Expr *p, int iCur){
   return exprIsConst(p, 3, iCur);
 }
 
+/*
+** Check pExpr to see if it is an invariant constraint on data source pSrc.
+** This is an optimization.  False negatives will perhaps cause slower
+** queries, but false positives will yield incorrect answers.  So when in
+** doubt, return 0.
+**
+** To be an invariant constraint, the following must be true:
+**
+**   (1)  pExpr cannot refer to any table other than pSrc->iCursor.
+**
+**   (2)  pExpr cannot use subqueries or non-deterministic functions.
+**
+**   (3)  pSrc cannot be part of the left operand for a RIGHT JOIN.
+**        (Is there some way to relax this constraint?)
+**
+**   (4)  If pSrc is the right operand of a LEFT JOIN, then...
+**         (4a)  pExpr must come from an ON clause..
+           (4b)  and specifically the ON clause associated with the LEFT JOIN.
+**
+**   (5)  If pSrc is not the right operand of a LEFT JOIN or the left
+**        operand of a RIGHT JOIN, then pExpr must be from the WHERE
+**        clause, not an ON clause.
+*/
+int sqlite3ExprIsTableConstraint(Expr *pExpr, const SrcItem *pSrc){
+  if( pSrc->fg.jointype & JT_LTORJ ){
+    return 0;  /* rule (3) */
+  }
+  if( pSrc->fg.jointype & JT_LEFT ){
+    if( !ExprHasProperty(pExpr, EP_FromJoin) ) return 0;  /* rule (4a) */
+    if( pExpr->w.iJoin!=pSrc->iCursor ) return 0;         /* rule (4b) */
+  }else{
+    if( ExprHasProperty(pExpr, EP_FromJoin) ) return 0;   /* rule (5) */
+  }
+  return sqlite3ExprIsTableConstant(pExpr, pSrc->iCursor); /* rules (1), (2) */
+}
+
 
 /*
 ** sqlite3WalkExpr() callback used by sqlite3ExprIsConstantOrGroupBy().
diff --git a/src/select.c b/src/select.c
index df4ad4395..3c59b5d5f 100644
--- a/src/select.c
+++ b/src/select.c
@@ -4329,6 +4329,7 @@ static int flattenSubquery(
 
     if( pSrc->nSrc>1 ){
       if( pParse->nSelect>500 ) return 0;
+      if( OptimizationDisabled(db, SQLITE_FlttnUnionAll) ) return 0;
       aCsrMap = sqlite3DbMallocZero(db, ((i64)pParse->nTab+1)*sizeof(int));
       if( aCsrMap ) aCsrMap[0] = pParse->nTab;
     }
@@ -4957,13 +4958,13 @@ static int pushDownWhereTerms(
   Parse *pParse,        /* Parse context (for malloc() and error reporting) */
   Select *pSubq,        /* The subquery whose WHERE clause is to be augmented */
   Expr *pWhere,         /* The WHERE clause of the outer query */
-  int iCursor,          /* Cursor number of the subquery */
-  int isLeftJoin        /* True if pSubq is the right term of a LEFT JOIN */
+  SrcItem *pSrc         /* The subquery term of the outer FROM clause */
 ){
   Expr *pNew;
   int nChng = 0;
   if( pWhere==0 ) return 0;
   if( pSubq->selFlags & (SF_Recursive|SF_MultiPart) ) return 0;
+  if( pSrc->fg.jointype & (JT_LTORJ|JT_RIGHT) ) return 0;
 
 #ifndef SQLITE_OMIT_WINDOWFUNC
   if( pSubq->pPrior ){
@@ -4993,10 +4994,11 @@ static int pushDownWhereTerms(
     return 0; /* restriction (3) */
   }
   while( pWhere->op==TK_AND ){
-    nChng += pushDownWhereTerms(pParse, pSubq, pWhere->pRight,
-                                iCursor, isLeftJoin);
+    nChng += pushDownWhereTerms(pParse, pSubq, pWhere->pRight, pSrc);
     pWhere = pWhere->pLeft;
   }
+
+#if 0  /* Legacy code. Checks now done by sqlite3ExprIsTableConstraint() */
   if( isLeftJoin
    && (ExprHasProperty(pWhere,EP_FromJoin)==0
          || pWhere->w.iJoin!=iCursor)
@@ -5008,7 +5010,9 @@ static int pushDownWhereTerms(
   ){
     return 0; /* restriction (5) */
   }
-  if( sqlite3ExprIsTableConstant(pWhere, iCursor) ){
+#endif
+
+  if( sqlite3ExprIsTableConstraint(pWhere, pSrc) ){
     nChng++;
     pSubq->selFlags |= SF_PushDown;
     while( pSubq ){
@@ -5016,8 +5020,8 @@ static int pushDownWhereTerms(
       pNew = sqlite3ExprDup(pParse->db, pWhere, 0);
       unsetJoinExpr(pNew, -1);
       x.pParse = pParse;
-      x.iTable = iCursor;
-      x.iNewTable = iCursor;
+      x.iTable = pSrc->iCursor;
+      x.iNewTable = pSrc->iCursor;
       x.isOuterJoin = 0;
       x.pEList = pSubq->pEList;
       pNew = substExpr(&x, pNew);
@@ -6870,9 +6874,7 @@ int sqlite3Select(
     if( OptimizationEnabled(db, SQLITE_PushDown)
      && (pItem->fg.isCte==0 
          || (pItem->u2.pCteUse->eM10d!=M10d_Yes && pItem->u2.pCteUse->nUse<2))
-     && (pItem->fg.jointype & JT_RIGHT)==0
-     && pushDownWhereTerms(pParse, pSub, p->pWhere, pItem->iCursor,
-                           (pItem->fg.jointype & JT_OUTER)!=0)
+     && pushDownWhereTerms(pParse, pSub, p->pWhere, pItem)
     ){
 #if TREETRACE_ENABLED
       if( sqlite3TreeTrace & 0x100 ){
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index d9f5bc42e..eb8ad2abe 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1780,6 +1780,7 @@ struct sqlite3 {
 #define SQLITE_BloomPulldown  0x00100000 /* Run Bloom filters early */
 #define SQLITE_BalancedMerge  0x00200000 /* Balance multi-way merges */
 #define SQLITE_ReleaseReg     0x00400000 /* Use OP_ReleaseReg for testing */
+#define SQLITE_FlttnUnionAll  0x00800000 /* Disable the UNION ALL flattener */
 #define SQLITE_AllOpts        0xffffffff /* All optimizations */
 
 /*
@@ -4753,6 +4754,7 @@ int sqlite3ExprIsConstantNotJoin(Expr*);
 int sqlite3ExprIsConstantOrFunction(Expr*, u8);
 int sqlite3ExprIsConstantOrGroupBy(Parse*, Expr*, ExprList*);
 int sqlite3ExprIsTableConstant(Expr*,int);
+int sqlite3ExprIsTableConstraint(Expr*,const SrcItem*);
 #ifdef SQLITE_ENABLE_CURSOR_HINTS
 int sqlite3ExprContainsSubquery(Expr*);
 #endif
diff --git a/src/where.c b/src/where.c
index d6c023941..2750d9358 100644
--- a/src/where.c
+++ b/src/where.c
@@ -832,9 +832,7 @@ static SQLITE_NOINLINE void constructAutomaticIndex(
     ** WHERE clause (or the ON clause of a LEFT join) that constrain which
     ** rows of the target table (pSrc) that can be used. */
     if( (pTerm->wtFlags & TERM_VIRTUAL)==0
-     && ((pSrc->fg.jointype&(JT_LEFT|JT_LTORJ))==0
-               || ExprHasProperty(pExpr,EP_FromJoin))
-     && sqlite3ExprIsTableConstant(pExpr, pSrc->iCursor)
+     && sqlite3ExprIsTableConstraint(pExpr, pSrc)
     ){
       pPartial = sqlite3ExprAnd(pParse, pPartial,
                                 sqlite3ExprDup(pParse->db, pExpr, 0));
@@ -1073,7 +1071,7 @@ static SQLITE_NOINLINE void sqlite3ConstructBloomFilter(
     for(pTerm=pWInfo->sWC.a; pTerm<pWCEnd; pTerm++){
       Expr *pExpr = pTerm->pExpr;
       if( (pTerm->wtFlags & TERM_VIRTUAL)==0
-       && sqlite3ExprIsTableConstant(pExpr, iCur)
+       && sqlite3ExprIsTableConstraint(pExpr, pItem)
       ){
         sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL);
       }