Remove a no-longer-needed kluge for degenerate aggregate cases,

and update some comments.

diff --git a/src/backend/executor/execQual.c b/src/backend/executor/execQual.c
index 81a1975a4a23755c3d016f07cb3bf907692914c7..2d972f5922990695ca8144035bb1ed250d5ad932 100644 (file)
--- a/src/backend/executor/execQual.c
+++ b/src/backend/executor/execQual.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.62 1999/09/26 21:21:09 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.63 1999/10/08 03:49:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -209,6 +209,9 @@ ExecEvalArrayRef(ArrayRef *arrayRef,
 static Datum
 ExecEvalAggref(Aggref *aggref, ExprContext *econtext, bool *isNull)
 {
+   if (econtext->ecxt_aggvalues == NULL) /* safety check */
+       elog(ERROR, "ExecEvalAggref: no aggregates in this expression context");
+
    *isNull = econtext->ecxt_aggnulls[aggref->aggno];
    return econtext->ecxt_aggvalues[aggref->aggno];
 }

diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index c37f4c4f42f9c49d520f04525fbe9e8cb76c0b1b..16b28060a68e67780998e25f15a07e69815dd204 100644 (file)
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -11,7 +11,7 @@
  *   SQL aggregates. (Do not expect POSTQUEL semantics.)    -- ay 2/95
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.56 1999/09/28 02:03:19 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.57 1999/10/08 03:49:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -136,12 +136,11 @@ copyDatum(Datum val, int typLen, bool typByVal)
  *   sfunc1 is never applied when the current tuple's aggregated_value
  *   is NULL.  sfunc2 is applied for each tuple if the aggref is marked
  *   'usenulls', otherwise it is only applied when aggregated_value is
- *   not NULL.  (usenulls is normally set only for the case of COUNT(*),
- *   since according to the SQL92 standard that is the only aggregate
- *   that considers nulls in its input.  SQL92 requires COUNT(*) and
- *   COUNT(field) to behave differently --- the latter doesn't count nulls
- *   --- so we can't make this flag a column of pg_aggregate but must
- *   set it according to usage.  Ugh.)
+ *   not NULL.  (usenulls was formerly used for COUNT(*), but is no longer
+ *   needed for that purpose; as of 10/1999 the support for usenulls is
+ *   dead code.  I have not removed it because it seems like a potentially
+ *   useful feature for user-defined aggregates.  We'd just need to add a
+ *   flag column to pg_aggregate and a parameter to CREATE AGGREGATE...)
  *
  *   If the outer subplan is a Group node, ExecAgg returns as many tuples
  *   as there are groups.
@@ -534,27 +533,14 @@ ExecInitAgg(Agg *node, EState *estate, Plan *parent)
    outerPlan = outerPlan(node);
    ExecInitNode(outerPlan, estate, (Plan *) node);
 
-   /*
-    * Result runs in its own context, but make it use our aggregates fix
-    * for 'select sum(2+2)'
-    */
-   if (IsA(outerPlan, Result))
-   {
-       ((Result *) outerPlan)->resstate->cstate.cs_ProjInfo->pi_exprContext->ecxt_aggvalues =
-           econtext->ecxt_aggvalues;
-       ((Result *) outerPlan)->resstate->cstate.cs_ProjInfo->pi_exprContext->ecxt_aggnulls =
-           econtext->ecxt_aggnulls;
-   }
-
    /* ----------------
-    *  initialize tuple type.
+    *  initialize source tuple type.
     * ----------------
     */
    ExecAssignScanTypeFromOuterPlan((Plan *) node, &aggstate->csstate);
 
    /*
-    * Initialize tuple type for both result and scan. This node does no
-    * projection
+    * Initialize result tuple type and projection info.
     */
    ExecAssignResultTypeFromTL((Plan *) node, &aggstate->csstate.cstate);
    ExecAssignProjectionInfo((Plan *) node, &aggstate->csstate.cstate);