From 411137a429210e432f923264a8e313a9872910ca Mon Sep 17 00:00:00 2001
From: David Rowley
Date: Wed, 24 Nov 2021 23:29:14 +1300
Subject: Flush Memoize cache when non-key parameters change, take 2

It's possible that a subplan below a Memoize node contains a parameter
from above the Memoize node.  If this parameter changes then cache entries
may become out-dated due to the new parameter value.

Previously Memoize was mistakenly not aware of this.  We fix this here by
flushing the cache whenever a parameter that's not part of the cache
key changes.

Bug: #17213
Reported by: Elvis Pranskevichus
Author: David Rowley
Discussion: https://postgr.es/m/17213-988ed34b225a2862@postgresql.org
Backpatch-through: 14, where Memoize was added
---
 src/include/nodes/execnodes.h | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'src/include/nodes/execnodes.h')

diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index d96ace32e43..ddc35293326 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -2113,6 +2113,8 @@ typedef struct MemoizeState
 								 * by bit, false when using hash equality ops */
 	MemoizeInstrumentation stats;	/* execution statistics */
 	SharedMemoizeInfo *shared_info; /* statistics for parallel workers */
+	Bitmapset	   *keyparamids; /* Param->paramids of expressions belonging to
+								  * param_exprs */
 } MemoizeState;
 
 /* ----------------
-- 
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