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Code review for IS DISTINCT FROM patch. Fix incorrect constant-folding

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logic, dissuade planner from thinking that 'x IS DISTINCT FROM 42' may
be optimized into 'x = 42' (!!), cause dependency on = operator to be
recorded correctly, minor other improvements.
This commit is contained in:
Tom Lane
2002-11-30 21:25:08 +00:00
parent 36c356e799
commit 2b7ec402c4
7 changed files with 70 additions and 115 deletions
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27
src/backend/executor/execQual.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.110 2002/11/25 21:29:35 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.111 2002/11/30 21:25:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1144,7 +1144,7 @@ ExecEvalFunc(Expr *funcClause,
* they are NULL; if either is NULL then the result is already
* known. If neither is NULL, then proceed to evaluate the
* function. Note that this is *always* derived from the equals
* operator, but since we've already evaluated the arguments
* operator, but since we need special processing of the arguments
* we can not simply reuse ExecEvalOper() or ExecEvalFunc().
* ----------------------------------------------------------------
*/
@ -1154,7 +1154,7 @@ ExecEvalDistinct(Expr *opClause,
bool *isNull,
ExprDoneCond *isDone)
{
bool result;
Datum result;
FunctionCachePtr fcache;
FunctionCallInfoData fcinfo;
ExprDoneCond argDone;
@ -1162,10 +1162,7 @@ ExecEvalDistinct(Expr *opClause,
List *argList;
/*
* we extract the oid of the function associated with the op and then
* pass the work onto ExecMakeFunctionResult which evaluates the
* arguments and returns the result of calling the function on the
* evaluated arguments.
* extract info from opClause
*/
op = (Oper *) opClause->oper;
argList = opClause->args;
@ -1181,34 +1178,36 @@ ExecEvalDistinct(Expr *opClause,
econtext->ecxt_per_query_memory);
op->op_fcache = fcache;
}
Assert(fcache->func.fn_retset == FALSE);
Assert(!fcache->func.fn_retset);
/* Need to prep callinfo structure */
MemSet(&fcinfo, 0, sizeof(fcinfo));
fcinfo.flinfo = &(fcache->func);
argDone = ExecEvalFuncArgs(&fcinfo, argList, econtext);
if (argDone != ExprSingleResult)
elog(ERROR, "IS DISTINCT FROM does not support set arguments");
Assert(fcinfo.nargs == 2);
if (fcinfo.argnull[0] && fcinfo.argnull[1])
{
/* Both NULL? Then is not distinct... */
result = FALSE;
result = BoolGetDatum(FALSE);
}
else if (fcinfo.argnull[0] || fcinfo.argnull[1])
{
/* One is NULL? Then is distinct... */
result = TRUE;
/* Only one is NULL? Then is distinct... */
result = BoolGetDatum(TRUE);
}
else
{
fcinfo.isnull = false;
result = FunctionCallInvoke(&fcinfo);
*isNull = fcinfo.isnull;
result = (!DatumGetBool(result));
/* Must invert result of "=" */
result = BoolGetDatum(!DatumGetBool(result));
}
return BoolGetDatum(result);
return result;
}
/* ----------------------------------------------------------------