v4-0003-RelationCopyStorageUsingBuffer-Use-generic-use-re.patch

From d5a743b4541d43abb5808696e72d50333a755ef7 Mon Sep 17 00:00:00 2001
From: Nazir Bilal Yavuz <byavuz81@gmail.com>
Date: Mon, 26 Aug 2024 12:24:26 +0300
Subject: [PATCH v4 3/5] RelationCopyStorageUsingBuffer: Use generic-use read
 stream struct and callback

Instead of creating another read stream struct and callback, use generic
one that is exported from read stream.
---
 src/backend/storage/buffer/bufmgr.c | 35 ++++-------------------------
 1 file changed, 4 insertions(+), 31 deletions(-)

diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 5cdd2f10fc8..7dc800888e0 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -136,33 +136,6 @@ typedef struct SMgrSortArray
 	SMgrRelation srel;
 } SMgrSortArray;
 
-/*
- * Helper struct for read stream object used in
- * RelationCopyStorageUsingBuffer() function.
- */
-struct copy_storage_using_buffer_read_stream_private
-{
-	BlockNumber blocknum;
-	BlockNumber nblocks;
-};
-
-/*
- * Callback function to get next block for read stream object used in
- * RelationCopyStorageUsingBuffer() function.
- */
-static BlockNumber
-copy_storage_using_buffer_read_stream_next_block(ReadStream *stream,
-												 void *callback_private_data,
-												 void *per_buffer_data)
-{
-	struct copy_storage_using_buffer_read_stream_private *p = callback_private_data;
-
-	if (p->blocknum < p->nblocks)
-		return p->blocknum++;
-
-	return InvalidBlockNumber;
-}
-
 /* GUC variables */
 bool		zero_damaged_pages = false;
 int			bgwriter_lru_maxpages = 100;
@@ -4710,7 +4683,7 @@ RelationCopyStorageUsingBuffer(RelFileLocator srclocator,
 	PGIOAlignedBlock buf;
 	BufferAccessStrategy bstrategy_src;
 	BufferAccessStrategy bstrategy_dst;
-	struct copy_storage_using_buffer_read_stream_private p;
+	BlockRangeReadStreamPrivate p;
 	ReadStream *src_stream;
 	SMgrRelation src_smgr;
 
@@ -4742,15 +4715,15 @@ RelationCopyStorageUsingBuffer(RelFileLocator srclocator,
 	bstrategy_dst = GetAccessStrategy(BAS_BULKWRITE);
 
 	/* Initalize streaming read */
-	p.blocknum = 0;
-	p.nblocks = nblocks;
+	p.current_blocknum = 0;
+	p.last_exclusive = nblocks;
 	src_smgr = smgropen(srclocator, INVALID_PROC_NUMBER);
 	src_stream = read_stream_begin_smgr_relation(READ_STREAM_FULL,
 												 bstrategy_src,
 												 src_smgr,
 												 permanent ? RELPERSISTENCE_PERMANENT : RELPERSISTENCE_UNLOGGED,
 												 forkNum,
-												 copy_storage_using_buffer_read_stream_next_block,
+												 block_range_read_stream_cb,
 												 &p,
 												 0);
 
-- 
2.45.2