*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.168 2004/08/29 05:06:42 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.169 2004/09/22 17:41:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
* ExecMakeTableFunctionResult
*
* Evaluate a table function, producing a materialized result in a Tuplestore
- * object. (If function returns an empty set, we just return NULL instead.)
+ * object. *returnDesc is set to the tupledesc actually returned by the
+ * function, or NULL if it didn't provide one.
*/
Tuplestorestate *
ExecMakeTableFunctionResult(ExprState *funcexpr,
TupleDesc tupdesc = NULL;
Oid funcrettype;
bool returnsTuple;
+ bool returnsSet = false;
FunctionCallInfoData fcinfo;
ReturnSetInfo rsinfo;
HeapTupleData tmptup;
bool direct_function_call;
bool first_time = true;
+ callerContext = CurrentMemoryContext;
+
+ funcrettype = exprType((Node *) funcexpr->expr);
+
+ returnsTuple = (funcrettype == RECORDOID ||
+ get_typtype(funcrettype) == 'c');
+
+ /*
+ * Prepare a resultinfo node for communication. We always do this
+ * even if not expecting a set result, so that we can pass
+ * expectedDesc. In the generic-expression case, the expression
+ * doesn't actually get to see the resultinfo, but set it up anyway
+ * because we use some of the fields as our own state variables.
+ */
+ MemSet(&fcinfo, 0, sizeof(fcinfo));
+ fcinfo.resultinfo = (Node *) &rsinfo;
+ rsinfo.type = T_ReturnSetInfo;
+ rsinfo.econtext = econtext;
+ rsinfo.expectedDesc = expectedDesc;
+ rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize);
+ rsinfo.returnMode = SFRM_ValuePerCall;
+ /* isDone is filled below */
+ rsinfo.setResult = NULL;
+ rsinfo.setDesc = NULL;
+
/*
* Normally the passed expression tree will be a FuncExprState, since
* the grammar only allows a function call at the top level of a table
init_fcache(func->funcid, fcache, econtext->ecxt_per_query_memory);
}
+ returnsSet = fcache->func.fn_retset;
/*
* Evaluate the function's argument list.
* the inner loop. So do it in caller context. Perhaps we should
* make a separate context just to hold the evaluated arguments?
*/
- MemSet(&fcinfo, 0, sizeof(fcinfo));
fcinfo.flinfo = &(fcache->func);
argDone = ExecEvalFuncArgs(&fcinfo, fcache->args, econtext);
/* We don't allow sets in the arguments of the table function */
/*
* If function is strict, and there are any NULL arguments, skip
- * calling the function and return NULL (actually an empty set).
+ * calling the function and act like it returned NULL (or an empty
+ * set, in the returns-set case).
*/
if (fcache->func.fn_strict)
{
for (i = 0; i < fcinfo.nargs; i++)
{
if (fcinfo.argnull[i])
- {
- *returnDesc = NULL;
- return NULL;
- }
+ goto no_function_result;
}
}
}
direct_function_call = false;
}
- funcrettype = exprType((Node *) funcexpr->expr);
-
- returnsTuple = (funcrettype == RECORDOID ||
- get_typtype(funcrettype) == 'c');
-
- /*
- * Prepare a resultinfo node for communication. We always do this
- * even if not expecting a set result, so that we can pass
- * expectedDesc. In the generic-expression case, the expression
- * doesn't actually get to see the resultinfo, but set it up anyway
- * because we use some of the fields as our own state variables.
- */
- fcinfo.resultinfo = (Node *) &rsinfo;
- rsinfo.type = T_ReturnSetInfo;
- rsinfo.econtext = econtext;
- rsinfo.expectedDesc = expectedDesc;
- rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize);
- rsinfo.returnMode = SFRM_ValuePerCall;
- /* isDone is filled below */
- rsinfo.setResult = NULL;
- rsinfo.setDesc = NULL;
-
/*
* Switch to short-lived context for calling the function or
* expression.
*/
- callerContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
+ MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
/*
* Loop to handle the ValuePerCall protocol (which is also the same
{
/*
* Check for end of result set.
- *
- * Note: if function returns an empty set, we don't build a
- * tupdesc or tuplestore (since we can't get a tupdesc in the
- * function-returning-tuple case)
*/
if (rsinfo.isDone == ExprEndResult)
break;
/*
- * Can't do anything useful with NULL rowtype values.
- * Currently we raise an error, but another alternative is to
- * just ignore the result and "continue" to get another row.
+ * Can't do anything very useful with NULL rowtype values.
+ * For a function returning set, we consider this a protocol
+ * violation (but another alternative would be to just ignore
+ * the result and "continue" to get another row). For a function
+ * not returning set, we fall out of the loop; we'll cons up
+ * an all-nulls result row below.
*/
if (returnsTuple && fcinfo.isnull)
+ {
+ if (!returnsSet)
+ break;
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
- errmsg("function returning row cannot return null value")));
+ errmsg("function returning set of rows cannot return null value")));
+ }
/*
* If first time through, build tupdesc and tuplestore for
first_time = false;
}
+no_function_result:
+
+ /*
+ * If we got nothing from the function (ie, an empty-set or NULL result),
+ * we have to create the tuplestore to return, and if it's a
+ * non-set-returning function then insert a single all-nulls row.
+ */
+ if (rsinfo.setResult == NULL)
+ {
+ MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
+ tupstore = tuplestore_begin_heap(true, false, work_mem);
+ rsinfo.setResult = tupstore;
+ if (!returnsSet)
+ {
+ int natts = expectedDesc->natts;
+ Datum *nulldatums;
+ char *nullflags;
+ HeapTuple tuple;
+
+ MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
+ nulldatums = (Datum *) palloc0(natts * sizeof(Datum));
+ nullflags = (char *) palloc(natts * sizeof(char));
+ memset(nullflags, 'n', natts * sizeof(char));
+ tuple = heap_formtuple(expectedDesc, nulldatums, nullflags);
+ MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
+ tuplestore_puttuple(tupstore, tuple);
+ }
+ }
+
MemoryContextSwitchTo(callerContext);
/* The returned pointers are those in rsinfo */
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