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Evaluate typeof(X) and length(Y) where X is any column and Y is a blob column

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without actually loading X and Y from disk.

FossilOrigin-Name: b899dbeb60752843287e2c6ad3577e1d00f0d587
This commit is contained in:
drh
2012-03-28 01:34:47 +00:00
parent cd217e7397
commit a748fdcc43
11 changed files with 148 additions and 51 deletions
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38
src/expr.c
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@@ -2032,15 +2032,6 @@ void sqlite3ExprCacheStore(Parse *pParse, int iTab, int iCol, int iReg){
*/
#ifndef NDEBUG
for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
#if 0 /* This code wold remove the entry from the cache if it existed */
if( p->iReg && p->iTable==iTab && p->iColumn==iCol ){
cacheEntryClear(pParse, p);
p->iLevel = pParse->iCacheLevel;
p->iReg = iReg;
p->lru = pParse->iCacheCnt++;
return;
}
#endif
assert( p->iReg==0 || p->iTable!=iTab || p->iColumn!=iCol );
}
#endif
@@ -2175,7 +2166,8 @@ int sqlite3ExprCodeGetColumn(
Table *pTab, /* Description of the table we are reading from */
int iColumn, /* Index of the table column */
int iTable, /* The cursor pointing to the table */
int iReg /* Store results here */
int iReg, /* Store results here */
u8 p5 /* P5 value for OP_Column */
){
Vdbe *v = pParse->pVdbe;
int i;
@@ -2190,7 +2182,11 @@ int sqlite3ExprCodeGetColumn(
}
assert( v!=0 );
sqlite3ExprCodeGetColumnOfTable(v, pTab, iTable, iColumn, iReg);
sqlite3ExprCacheStore(pParse, iTable, iColumn, iReg);
if( p5 ){
sqlite3VdbeChangeP5(v, p5);
}else{
sqlite3ExprCacheStore(pParse, iTable, iColumn, iReg);
}
return iReg;
}
@@ -2318,7 +2314,8 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
inReg = pExpr->iColumn + pParse->ckBase;
}else{
inReg = sqlite3ExprCodeGetColumn(pParse, pExpr->pTab,
pExpr->iColumn, pExpr->iTable, target);
pExpr->iColumn, pExpr->iTable, target,
pExpr->op2);
}
break;
}
@@ -2595,6 +2592,23 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
if( pFarg ){
r1 = sqlite3GetTempRange(pParse, nFarg);
/* For length() and typeof() functions with a column argument,
** set the P5 parameter to the OP_Column opcode to OPFLAG_LENGTHARG
** or OPFLAG_TYPEOFARG respectively, to avoid unnecessary data
** loading.
*/
if( (pDef->flags & (SQLITE_FUNC_LENGTH|SQLITE_FUNC_TYPEOF))!=0 ){
assert( nFarg==1 );
assert( pFarg->a[0].pExpr!=0 );
if( pFarg->a[0].pExpr->op==TK_COLUMN ){
assert( SQLITE_FUNC_LENGTH==OPFLAG_LENGTHARG );
assert( SQLITE_FUNC_TYPEOF==OPFLAG_TYPEOFARG );
testcase( pDef->flags==SQLITE_FUNC_LENGTH );
pFarg->a[0].pExpr->op2 = pDef->flags;
}
}
sqlite3ExprCachePush(pParse); /* Ticket 2ea2425d34be */
sqlite3ExprCodeExprList(pParse, pFarg, r1, 1);
sqlite3ExprCachePop(pParse, 1); /* Ticket 2ea2425d34be */