0001-Refactor-PinBufferForBlock-to-remove-if-checks-about.patch

From 04fd860ce8c4c57830930cb362799fd155c92613 Mon Sep 17 00:00:00 2001
From: Nazir Bilal Yavuz <byavuz81@gmail.com>
Date: Sun, 7 Apr 2024 22:33:36 +0300
Subject: [PATCH 1/2] Refactor PinBufferForBlock() to remove if checks about
 persistence

There are if checks in PinBufferForBlock() function to set persistence
of the relation and this function is called for the each block in the
relation. Instead of that, set persistence of the relation before
PinBufferForBlock() function.
---
 src/backend/storage/aio/read_stream.c |  2 +-
 src/backend/storage/buffer/bufmgr.c   | 31 +++++++++++----------------
 2 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/src/backend/storage/aio/read_stream.c b/src/backend/storage/aio/read_stream.c
index f54dacdd914..d155dde5ce3 100644
--- a/src/backend/storage/aio/read_stream.c
+++ b/src/backend/storage/aio/read_stream.c
@@ -549,7 +549,7 @@ read_stream_begin_relation(int flags,
 	{
 		stream->ios[i].op.rel = rel;
 		stream->ios[i].op.smgr = RelationGetSmgr(rel);
-		stream->ios[i].op.smgr_persistence = 0;
+		stream->ios[i].op.smgr_persistence = rel->rd_rel->relpersistence;
 		stream->ios[i].op.forknum = forknum;
 		stream->ios[i].op.strategy = strategy;
 	}
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 06e9ffd2b00..b4fcefed78a 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -1067,24 +1067,10 @@ PinBufferForBlock(Relation rel,
 	BufferDesc *bufHdr;
 	IOContext	io_context;
 	IOObject	io_object;
-	char		persistence;
 
 	Assert(blockNum != P_NEW);
 
-	/*
-	 * If there is no Relation it usually implies recovery and thus permanent,
-	 * but we take an argmument because CreateAndCopyRelationData can reach us
-	 * with only an SMgrRelation for an unlogged relation that we don't want
-	 * to flag with BM_PERMANENT.
-	 */
-	if (rel)
-		persistence = rel->rd_rel->relpersistence;
-	else if (smgr_persistence == 0)
-		persistence = RELPERSISTENCE_PERMANENT;
-	else
-		persistence = smgr_persistence;
-
-	if (persistence == RELPERSISTENCE_TEMP)
+	if (smgr_persistence == RELPERSISTENCE_TEMP)
 	{
 		io_context = IOCONTEXT_NORMAL;
 		io_object = IOOBJECT_TEMP_RELATION;
@@ -1101,7 +1087,7 @@ PinBufferForBlock(Relation rel,
 									   smgr->smgr_rlocator.locator.relNumber,
 									   smgr->smgr_rlocator.backend);
 
-	if (persistence == RELPERSISTENCE_TEMP)
+	if (smgr_persistence == RELPERSISTENCE_TEMP)
 	{
 		bufHdr = LocalBufferAlloc(smgr, forkNum, blockNum, foundPtr);
 		if (*foundPtr)
@@ -1109,7 +1095,7 @@ PinBufferForBlock(Relation rel,
 	}
 	else
 	{
-		bufHdr = BufferAlloc(smgr, persistence, forkNum, blockNum,
+		bufHdr = BufferAlloc(smgr, smgr_persistence, forkNum, blockNum,
 							 strategy, foundPtr, io_context);
 		if (*foundPtr)
 			pgBufferUsage.shared_blks_hit++;
@@ -1157,6 +1143,7 @@ ReadBuffer_common(Relation rel, SMgrRelation smgr, char smgr_persistence,
 	ReadBuffersOperation operation;
 	Buffer		buffer;
 	int			flags;
+	char		persistence;
 
 	/*
 	 * Backward compatibility path, most code should use ExtendBufferedRel()
@@ -1195,7 +1182,15 @@ ReadBuffer_common(Relation rel, SMgrRelation smgr, char smgr_persistence,
 		flags = 0;
 	operation.smgr = smgr;
 	operation.rel = rel;
-	operation.smgr_persistence = smgr_persistence;
+
+	if (rel)
+		persistence = rel->rd_rel->relpersistence;
+	else if (smgr_persistence == 0)
+		persistence = RELPERSISTENCE_PERMANENT;
+	else
+		persistence = smgr_persistence;
+	operation.smgr_persistence = persistence;
+
 	operation.forknum = forkNum;
 	operation.strategy = strategy;
 	if (StartReadBuffer(&operation,
-- 
2.43.0