From 11c1d555cebe8045a45bc0ee10d0673fad8d4895 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Sat, 28 Oct 2017 11:50:22 +0200
Subject: [PATCH] Improve comments for parallel executor estimation functions.

The previous comment (which was copied as boilerplate from one file
to the next) implied that it was the executor node itself which was
being serialized, but that's not right.  We're not serializing
the executor nodes; we're just allowing them to store some
additional information in DSM.  Adjusts the comment to reflect this.

Discussion: http://postgr.es/m/CA+TgmoaHVinxG=3h6qBAsyV8xaDyQwbzK7YZnYfE8nJFMK1=FA@mail.gmail.com
---
 src/backend/executor/nodeBitmapHeapscan.c | 3 ++-
 src/backend/executor/nodeIndexonlyscan.c  | 3 ++-
 src/backend/executor/nodeIndexscan.c      | 3 ++-
 src/backend/executor/nodeSeqscan.c        | 3 ++-
 4 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c
index f7e55e0b45..6035b4dfd4 100644
--- a/src/backend/executor/nodeBitmapHeapscan.c
+++ b/src/backend/executor/nodeBitmapHeapscan.c
@@ -934,7 +934,8 @@ BitmapShouldInitializeSharedState(ParallelBitmapHeapState *pstate)
 /* ----------------------------------------------------------------
  *		ExecBitmapHeapEstimate
  *
- *		estimates the space required to serialize bitmap scan node.
+ *		Compute the amount of space we'll need in the parallel
+ *		query DSM, and inform pcxt->estimator about our needs.
  * ----------------------------------------------------------------
  */
 void
diff --git a/src/backend/executor/nodeIndexonlyscan.c b/src/backend/executor/nodeIndexonlyscan.c
index 5351cb8981..9368ca04f8 100644
--- a/src/backend/executor/nodeIndexonlyscan.c
+++ b/src/backend/executor/nodeIndexonlyscan.c
@@ -604,7 +604,8 @@ ExecInitIndexOnlyScan(IndexOnlyScan *node, EState *estate, int eflags)
 /* ----------------------------------------------------------------
  *		ExecIndexOnlyScanEstimate
  *
- *	estimates the space required to serialize index-only scan node.
+ *		Compute the amount of space we'll need in the parallel
+ *		query DSM, and inform pcxt->estimator about our needs.
  * ----------------------------------------------------------------
  */
 void
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index 638b17b07c..262008240d 100644
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -1644,7 +1644,8 @@ ExecIndexBuildScanKeys(PlanState *planstate, Relation index,
 /* ----------------------------------------------------------------
  *		ExecIndexScanEstimate
  *
- *		estimates the space required to serialize indexscan node.
+ *		Compute the amount of space we'll need in the parallel
+ *		query DSM, and inform pcxt->estimator about our needs.
  * ----------------------------------------------------------------
  */
 void
diff --git a/src/backend/executor/nodeSeqscan.c b/src/backend/executor/nodeSeqscan.c
index d4ac939c9b..76bec780a8 100644
--- a/src/backend/executor/nodeSeqscan.c
+++ b/src/backend/executor/nodeSeqscan.c
@@ -289,7 +289,8 @@ ExecReScanSeqScan(SeqScanState *node)
 /* ----------------------------------------------------------------
  *		ExecSeqScanEstimate
  *
- *		estimates the space required to serialize seqscan node.
+ *		Compute the amount of space we'll need in the parallel
+ *		query DSM, and inform pcxt->estimator about our needs.
  * ----------------------------------------------------------------
  */
 void