C comment: add description of root_tuple_slot

Reported-by: Amit Langote
Discussion: https://postgr.es/m/d2e6674c-c5c6-fe89-1d0b-3534b9db0476@lab.ntt.co.jp

diff --git a/src/include/executor/execPartition.h b/src/include/executor/execPartition.h
index 8f847050e497585657e9bbab029500a2c4e91c23..fc6e9574e302927bb2c18018bea24dfb3774afb1 100644 (file)
--- a/src/include/executor/execPartition.h
+++ b/src/include/executor/execPartition.h
@@ -90,6 +90,10 @@ typedef struct PartitionDispatchData *PartitionDispatch;
  *                             given leaf partition's rowtype after that
  *                             partition is chosen for insertion by
  *                             tuple-routing.
+ * root_tuple_slot             TupleTableSlot to be used to transiently hold
+ *                             copy of a tuple that's being moved across
+ *                             partitions in the root partitioned table's
+ *                             rowtype
  *-----------------------
  */
 typedef struct PartitionTupleRouting