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Fix handling of covering indexes that use virtual columns.

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FossilOrigin-Name: e0f7e321eca91c49102649f70728de69347cbd7b16599b854203c24cfdc348e6
This commit is contained in:
drh
2019-10-24 20:29:25 +00:00
parent 035f6d909f
commit c7476735c9
5 changed files with 72 additions and 19 deletions
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52
src/wherecode.c
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@@ -1106,6 +1106,7 @@ typedef struct IdxExprTrans {
int iTabCur; /* The cursor of the corresponding table */
int iIdxCur; /* The cursor for the index */
int iIdxCol; /* The column for the index */
int iTabCol; /* The column for the table */
} IdxExprTrans;
/* The walker node callback used to transform matching expressions into
@@ -1128,10 +1129,30 @@ static int whereIndexExprTransNode(Walker *p, Expr *pExpr){
}
}
#ifndef SQLITE_OMIT_GENERATED_COLUMNS
/* A walker node callback that translates a column reference to a table
** into a corresponding column reference of an index.
*/
static int whereIndexExprTransColumn(Walker *p, Expr *pExpr){
if( pExpr->op==TK_COLUMN ){
IdxExprTrans *pX = p->u.pIdxTrans;
if( pExpr->iTable==pX->iTabCur && pExpr->iColumn==pX->iTabCol ){
pExpr->iTable = pX->iIdxCur;
pExpr->iColumn = pX->iIdxCol;
}
}
return WRC_Continue;
}
#endif /* SQLITE_OMIT_GENERATED_COLUMNS */
/*
** For an indexes on expression X, locate every instance of expression X
** in pExpr and change that subexpression into a reference to the appropriate
** column of the index.
**
** 2019-10-24: Updated to also translate references to a VIRTUAL column in
** the table into references to the corresponding (stored) column of the
** index.
*/
static void whereIndexExprTrans(
Index *pIdx, /* The Index */
@@ -1141,20 +1162,35 @@ static void whereIndexExprTrans(
){
int iIdxCol; /* Column number of the index */
ExprList *aColExpr; /* Expressions that are indexed */
Table *pTab;
Walker w;
IdxExprTrans x;
aColExpr = pIdx->aColExpr;
if( aColExpr==0 ) return; /* Not an index on expressions */
if( aColExpr==0 && !pIdx->bHasVCol ){
/* The index does not reference any expressions or virtual columns
** so no translations are needed. */
return;
}
pTab = pIdx->pTable;
memset(&w, 0, sizeof(w));
w.xExprCallback = whereIndexExprTransNode;
w.u.pIdxTrans = &x;
x.iTabCur = iTabCur;
x.iIdxCur = iIdxCur;
for(iIdxCol=0; iIdxCol<aColExpr->nExpr; iIdxCol++){
if( pIdx->aiColumn[iIdxCol]!=XN_EXPR ) continue;
assert( aColExpr->a[iIdxCol].pExpr!=0 );
for(iIdxCol=0; iIdxCol<pIdx->nColumn; iIdxCol++){
i16 iRef = pIdx->aiColumn[iIdxCol];
if( iRef==XN_EXPR ){
assert( aColExpr->a[iIdxCol].pExpr!=0 );
x.pIdxExpr = aColExpr->a[iIdxCol].pExpr;
w.xExprCallback = whereIndexExprTransNode;
#ifndef SQLITE_OMIT_GENERATED_COLUMNS
}else if( iRef>=0 && (pTab->aCol[iRef].colFlags & COLFLAG_VIRTUAL)!=0 ){
x.iTabCol = iRef;
w.xExprCallback = whereIndexExprTransColumn;
#endif /* SQLITE_OMIT_GENERATED_COLUMNS */
}else{
continue;
}
x.iIdxCol = iIdxCol;
x.pIdxExpr = aColExpr->a[iIdxCol].pExpr;
sqlite3WalkExpr(&w, pWInfo->pWhere);
sqlite3WalkExprList(&w, pWInfo->pOrderBy);
sqlite3WalkExprList(&w, pWInfo->pResultSet);
@@ -1835,7 +1871,9 @@ Bitmask sqlite3WhereCodeOneLoopStart(
/* If pIdx is an index on one or more expressions, then look through
** all the expressions in pWInfo and try to transform matching expressions
** into reference to index columns.
** into reference to index columns. Also attempt to translate references
** to virtual columns in the table into references to (stored) columns
** of the index.
**
** Do not do this for the RHS of a LEFT JOIN. This is because the
** expression may be evaluated after OP_NullRow has been executed on