*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.220 2007/06/11 22:22:40 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.221 2007/08/31 18:33:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
bool *isNull, ExprDoneCond *isDone);
static Datum ExecEvalWholeRowVar(ExprState *exprstate, ExprContext *econtext,
bool *isNull, ExprDoneCond *isDone);
+static Datum ExecEvalWholeRowSlow(ExprState *exprstate, ExprContext *econtext,
+ bool *isNull, ExprDoneCond *isDone);
static Datum ExecEvalConst(ExprState *exprstate, ExprContext *econtext,
bool *isNull, ExprDoneCond *isDone);
static Datum ExecEvalParam(ExprState *exprstate, ExprContext *econtext,
*
* Note: ExecEvalVar is executed only the first time through in a given plan;
* it changes the ExprState's function pointer to pass control directly to
- * ExecEvalScalarVar or ExecEvalWholeRowVar after making one-time checks.
+ * ExecEvalScalarVar, ExecEvalWholeRowVar, or ExecEvalWholeRowSlow after
+ * making one-time checks.
* ----------------------------------------------------------------
*/
static Datum
* the actual tuple type is compatible with it.
*/
TupleDesc slot_tupdesc = slot->tts_tupleDescriptor;
+ bool needslow = false;
if (variable->vartype == RECORDOID)
{
* Also, we can ignore type mismatch on columns that are dropped
* in the destination type, so long as the physical storage
* matches. This is helpful in some cases involving out-of-date
- * cached plans.
+ * cached plans. Also, we have to allow the case that the slot
+ * has more columns than the Var's type, because we might be
+ * looking at the output of a subplan that includes resjunk
+ * columns. (XXX it would be nice to verify that the extra
+ * columns are all marked resjunk, but we haven't got access to
+ * the subplan targetlist here...) Resjunk columns should always
+ * be at the end of a targetlist, so it's sufficient to ignore
+ * them here; but we need to use ExecEvalWholeRowSlow to get
+ * rid of them in the eventual output tuples.
*/
var_tupdesc = lookup_rowtype_tupdesc(variable->vartype, -1);
- if (var_tupdesc->natts != slot_tupdesc->natts)
+ if (var_tupdesc->natts > slot_tupdesc->natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("table row type and query-specified row type do not match"),
errdetail("Table row contains %d attributes, but query expects %d.",
slot_tupdesc->natts, var_tupdesc->natts)));
+ else if (var_tupdesc->natts < slot_tupdesc->natts)
+ needslow = true;
for (i = 0; i < var_tupdesc->natts; i++)
{
}
/* Skip the checking on future executions of node */
- exprstate->evalfunc = ExecEvalWholeRowVar;
+ if (needslow)
+ exprstate->evalfunc = ExecEvalWholeRowSlow;
+ else
+ exprstate->evalfunc = ExecEvalWholeRowVar;
/* Fetch the value */
return ExecEvalWholeRowVar(exprstate, econtext, isNull, isDone);
return PointerGetDatum(dtuple);
}
+/* ----------------------------------------------------------------
+ * ExecEvalWholeRowSlow
+ *
+ * Returns a Datum for a whole-row variable, in the "slow" case where
+ * we can't just copy the subplan's output.
+ * ----------------------------------------------------------------
+ */
+static Datum
+ExecEvalWholeRowSlow(ExprState *exprstate, ExprContext *econtext,
+ bool *isNull, ExprDoneCond *isDone)
+{
+ Var *variable = (Var *) exprstate->expr;
+ TupleTableSlot *slot = econtext->ecxt_scantuple;
+ HeapTuple tuple;
+ TupleDesc var_tupdesc;
+ HeapTupleHeader dtuple;
+
+ if (isDone)
+ *isDone = ExprSingleResult;
+ *isNull = false;
+
+ /*
+ * Currently, the only case handled here is stripping of trailing
+ * resjunk fields, which we do in a slightly chintzy way by just
+ * adjusting the tuple's natts header field. Possibly there will someday
+ * be a need for more-extensive rearrangements, in which case it'd
+ * be worth disassembling and reassembling the tuple (perhaps use a
+ * JunkFilter for that?)
+ */
+ Assert(variable->vartype != RECORDOID);
+ var_tupdesc = lookup_rowtype_tupdesc(variable->vartype, -1);
+
+ tuple = ExecFetchSlotTuple(slot);
+
+ /*
+ * We have to make a copy of the tuple so we can safely insert the Datum
+ * overhead fields, which are not set in on-disk tuples; not to mention
+ * fooling with its natts field.
+ */
+ dtuple = (HeapTupleHeader) palloc(tuple->t_len);
+ memcpy((char *) dtuple, (char *) tuple->t_data, tuple->t_len);
+
+ HeapTupleHeaderSetDatumLength(dtuple, tuple->t_len);
+ HeapTupleHeaderSetTypeId(dtuple, variable->vartype);
+ HeapTupleHeaderSetTypMod(dtuple, variable->vartypmod);
+
+ Assert(HeapTupleHeaderGetNatts(dtuple) >= var_tupdesc->natts);
+ HeapTupleHeaderSetNatts(dtuple, var_tupdesc->natts);
+
+ ReleaseTupleDesc(var_tupdesc);
+
+ return PointerGetDatum(dtuple);
+}
+
/* ----------------------------------------------------------------
* ExecEvalConst
*