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-rw-r--r--src/backend/optimizer/prep/prepunion.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c
index 3b9e740cadf..3bf7223199f 100644
--- a/src/backend/optimizer/prep/prepunion.c
+++ b/src/backend/optimizer/prep/prepunion.c
@@ -22,7 +22,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.132 2006/04/30 18:30:39 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.133 2006/08/10 02:36:28 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -152,6 +152,10 @@ plan_set_operations(PlannerInfo *root, double tuple_fraction,
* flag: if >= 0, add a resjunk output column indicating value of flag
* refnames_tlist: targetlist to take column names from
* *sortClauses: receives list of SortClauses for result plan, if any
+ *
+ * We don't have to care about typmods here: the only allowed difference
+ * between set-op input and output typmods is input is a specific typmod
+ * and output is -1, and that does not require a coercion.
*/
static Plan *
recurse_set_operations(Node *setOp, PlannerInfo *root,