opensourcemirror
/
postgresql
mirror of git://git.postgresql.org/git/postgresql.git
1
0
Fork 0
Code Issues Releases Wiki Activity

Fix nodeAgg coredump in case where lower-level plan has 

an empty targetlist *and* fails to return any tuples, as will happen
for example with 'SELECT COUNT(1) FROM table WHERE ...' if the where-
clause selects no tuples.  It's so nice to make a fix by diking out code,
instead of adding more...
This commit is contained in:
Tom Lane 1999-09-28 02:03:19 +00:00
parent 04f150e607
commit a55888ec9c
1 changed files with 14 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
src/backend/executor/nodeAgg.c
View File

@ -11,7 +11,7 @@
* SQL aggregates. (Do not expect POSTQUEL semantics.) -- ay 2/95
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.55 1999/09/26 21:21:09 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.56 1999/09/28 02:03:19 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -373,7 +373,8 @@ ExecAgg(Agg *node)
elog(ERROR, "ExecAgg: no valid transition functions??");
/*
* Release any per-group working storage.
* Release any per-group working storage, unless we're passing
* it back as the result of the aggregate.
*/
if (OidIsValid(peraggstate->xfn1_oid) &&
! peraggstate->value1IsNull &&
@ -411,34 +412,20 @@ ExecAgg(Agg *node)
aggstate->agg_done = true;
/*
* When the outerPlan doesn't return a single tuple,
* create a dummy input tuple anyway because we still need
* to return a valid aggregate tuple. (XXX isn't this wasted
* effort? Since we're not in GROUP BY mode, it shouldn't be
* possible for the projected result to refer to any raw input
* columns??) The values returned for the aggregates will be
* the initial values of the transition functions.
* We used to create a dummy all-nulls input tuple here if
* inputTuple == NULL (ie, the outerPlan didn't return anything).
* However, now that we don't return a bogus tuple in Group mode,
* we can only get here with inputTuple == NULL in non-Group mode.
* So, if the parser has done its job right, the projected output
* tuple's targetList must not contain any direct references to
* input columns, and so it's a waste of time to create an
* all-nulls input tuple. We just let the tuple slot get set
* to NULL instead. The values returned for the aggregates will
* be the initial values of the transition functions.
*/
if (inputTuple == NULL)
{
TupleDesc tupType;
Datum *tupValue;
char *null_array;
AttrNumber attnum;
tupType = aggstate->csstate.css_ScanTupleSlot->ttc_tupleDescriptor;
tupValue = projInfo->pi_tupValue;
/* set all the values to NULL */
null_array = palloc(sizeof(char) * tupType->natts);
for (attnum = 0; attnum < tupType->natts; attnum++)
null_array[attnum] = 'n';
inputTuple = heap_formtuple(tupType, tupValue, null_array);
pfree(null_array);
}
/*
* Store the representative input tuple (or faked-up null tuple)
* Store the representative input tuple (or NULL, if none)
* in the tuple table slot reserved for it.
*/
ExecStoreTuple(inputTuple,