v1-0001-Fix-GIN-fast-path-XLogBeginInsert-and-Read-LockBu.patch

From 05d0b9209ec5636e8b017b2d1050767517a96cd7 Mon Sep 17 00:00:00 2001
From: Matthias van de Meent <boekewurm+postgres@gmail.com>
Date: Thu, 8 Sep 2022 12:38:15 +0200
Subject: [PATCH v1] Fix GIN fast-path XLogBeginInsert() and Read/LockBuffer
 ordering issue

XLogBeginInsert() should be called only after the caller has locked all
relevant buffers, and starting a critical section (where and when
applicable), according to the XLog Manual in access/transam/README,
section "Write-Ahead Log Coding".
---
 src/backend/access/gin/ginfast.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/backend/access/gin/ginfast.c b/src/backend/access/gin/ginfast.c
index 6c677447a9..5784c365bf 100644
--- a/src/backend/access/gin/ginfast.c
+++ b/src/backend/access/gin/ginfast.c
@@ -285,9 +285,6 @@ ginHeapTupleFastInsert(GinState *ginstate, GinTupleCollector *collector)
 		memset(&sublist, 0, sizeof(GinMetaPageData));
 		makeSublist(index, collector->tuples, collector->ntuples, &sublist);
 
-		if (needWal)
-			XLogBeginInsert();
-
 		/*
 		 * metapage was unlocked, see above
 		 */
@@ -307,6 +304,9 @@ ginHeapTupleFastInsert(GinState *ginstate, GinTupleCollector *collector)
 
 			metadata->nPendingPages = sublist.nPendingPages;
 			metadata->nPendingHeapTuples = sublist.nPendingHeapTuples;
+
+			if (needWal)
+				XLogBeginInsert();
 		}
 		else
 		{
@@ -335,7 +335,10 @@ ginHeapTupleFastInsert(GinState *ginstate, GinTupleCollector *collector)
 			metadata->nPendingHeapTuples += sublist.nPendingHeapTuples;
 
 			if (needWal)
+			{
+				XLogBeginInsert();
 				XLogRegisterBuffer(1, buffer, REGBUF_STANDARD);
+			}
 		}
 	}
 	else
-- 
2.30.2