v12-0002-Extend-bufmgr-interfaces.patch

From f8dda8ea34673ab12872c7d3bcc7e95610d86f1a Mon Sep 17 00:00:00 2001
From: Dilip Kumar <dilipkumar@localhost.localdomain>
Date: Thu, 10 Feb 2022 15:55:33 +0530
Subject: [PATCH v12 2/4] Extend bufmgr interfaces

Extend ReadBufferWithoutRelcache interface to take relpersistence
as input. At present, this function may only be used on permanent
relations, because we only use it during XLOG replay.  But now as
part of the bigger patch set, we will be using this for reading the
buffer from the database which we are not connected so now we might
have temporary and unlogged relations as well.
---
 src/backend/access/transam/xlogutils.c |  9 ++++++---
 src/backend/storage/buffer/bufmgr.c    | 11 ++---------
 src/include/storage/bufmgr.h           |  3 ++-
 3 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c
index 54d5f20..c292794 100644
--- a/src/backend/access/transam/xlogutils.c
+++ b/src/backend/access/transam/xlogutils.c
@@ -484,7 +484,8 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 	{
 		/* page exists in file */
 		buffer = ReadBufferWithoutRelcache(rnode, forknum, blkno,
-										   mode, NULL);
+										   mode, NULL,
+										   RELPERSISTENCE_PERMANENT);
 	}
 	else
 	{
@@ -509,7 +510,8 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 				ReleaseBuffer(buffer);
 			}
 			buffer = ReadBufferWithoutRelcache(rnode, forknum,
-											   P_NEW, mode, NULL);
+											   P_NEW, mode, NULL,
+											   RELPERSISTENCE_PERMANENT);
 		}
 		while (BufferGetBlockNumber(buffer) < blkno);
 		/* Handle the corner case that P_NEW returns non-consecutive pages */
@@ -519,7 +521,8 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 				LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
 			ReleaseBuffer(buffer);
 			buffer = ReadBufferWithoutRelcache(rnode, forknum, blkno,
-											   mode, NULL);
+											   mode, NULL,
+											   RELPERSISTENCE_PERMANENT);
 		}
 	}
 
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index f5459c6..0ed2d31 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -771,24 +771,17 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 /*
  * ReadBufferWithoutRelcache -- like ReadBufferExtended, but doesn't require
  *		a relcache entry for the relation.
- *
- * NB: At present, this function may only be used on permanent relations, which
- * is OK, because we only use it during XLOG replay.  If in the future we
- * want to use it on temporary or unlogged relations, we could pass additional
- * parameters.
  */
 Buffer
 ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 						  BlockNumber blockNum, ReadBufferMode mode,
-						  BufferAccessStrategy strategy)
+						  BufferAccessStrategy strategy, char relpersistence)
 {
 	bool		hit;
 
 	SMgrRelation smgr = smgropen(rnode, InvalidBackendId);
 
-	Assert(InRecovery);
-
-	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
+	return ReadBuffer_common(smgr, relpersistence, forkNum, blockNum,
 							 mode, strategy, &hit);
 }
 
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index dd01841..7b80f58 100644
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -184,7 +184,8 @@ extern Buffer ReadBufferExtended(Relation reln, ForkNumber forkNum,
 								 BufferAccessStrategy strategy);
 extern Buffer ReadBufferWithoutRelcache(RelFileNode rnode,
 										ForkNumber forkNum, BlockNumber blockNum,
-										ReadBufferMode mode, BufferAccessStrategy strategy);
+										ReadBufferMode mode, BufferAccessStrategy strategy,
+										char relpersistence);
 extern void ReleaseBuffer(Buffer buffer);
 extern void UnlockReleaseBuffer(Buffer buffer);
 extern void MarkBufferDirty(Buffer buffer);
-- 
1.8.3.1