From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Wed, 1 Apr 2026 20:56:51 +0000 (+0300)
Subject: Make ShmemIndex visible in the pg_shmem_allocations view
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1bdbb211bbf31b0024f000746c42326648ecde90;p=thirdparty%2Fpostgresql.git

Make ShmemIndex visible in the pg_shmem_allocations view

Reviewed-by: Tomas Vondra <tomas@vondra.me>
Discussion: https://www.postgresql.org/message-id/01ab1d41-3eda-4705-8bbd-af898f5007f1@iki.fi
---

diff --git a/src/backend/storage/ipc/shmem.c b/src/backend/storage/ipc/shmem.c
index 0e49debaaac..a5b7360e2dc 100644
--- a/src/backend/storage/ipc/shmem.c
+++ b/src/backend/storage/ipc/shmem.c
@@ -131,7 +131,7 @@ InitShmemAllocator(PGShmemHeader *seghdr)
 	Size		offset;
 	HASHCTL		info;
 	int			hash_flags;
-	size_t		size;
+	size_t		size = 0;
 
 #ifndef EXEC_BACKEND
 	Assert(!IsUnderPostmaster);
@@ -198,6 +198,22 @@ InitShmemAllocator(PGShmemHeader *seghdr)
 	info.hctl = ShmemAllocator->index;
 	ShmemIndex = hash_create("ShmemIndex", SHMEM_INDEX_SIZE, &info, hash_flags);
 	Assert(ShmemIndex != NULL);
+
+	/*
+	 * Add an entry for ShmemIndex itself into ShmemIndex, so that it's
+	 * visible in the pg_shmem_allocations view
+	 */
+	if (!IsUnderPostmaster)
+	{
+		bool		found;
+		ShmemIndexEnt *result = (ShmemIndexEnt *)
+			hash_search(ShmemIndex, "ShmemIndex", HASH_ENTER, &found);
+
+		Assert(!found);
+		result->size = size;
+		result->allocated_size = size;
+		result->location = ShmemAllocator->index;
+	}
 }
 
 /*