Add block_range_read_stream_cb(), to deduplicate code.

This replaces two functions for iterating over all blocks in a range.  A
pending patch will use this instead of adding a third.

Nazir Bilal Yavuz

Discussion: https://postgr.es/m/20240820184742[email protected]

diff --git a/contrib/pg_prewarm/pg_prewarm.c b/contrib/pg_prewarm/pg_prewarm.c
index 5c859e983c5cac6266e84bd85521ca33bec014bd..243d36c46e896497e7b8357af960f36015947997 100644 (file)
--- a/contrib/pg_prewarm/pg_prewarm.c
+++ b/contrib/pg_prewarm/pg_prewarm.c
@@ -39,25 +39,6 @@ typedef enum
 
 static PGIOAlignedBlock blockbuffer;
 
-struct pg_prewarm_read_stream_private
-{
-   BlockNumber blocknum;
-   int64       last_block;
-};
-
-static BlockNumber
-pg_prewarm_read_stream_next_block(ReadStream *stream,
-                                 void *callback_private_data,
-                                 void *per_buffer_data)
-{
-   struct pg_prewarm_read_stream_private *p = callback_private_data;
-
-   if (p->blocknum <= p->last_block)
-       return p->blocknum++;
-
-   return InvalidBlockNumber;
-}
-
 /*
  * pg_prewarm(regclass, mode text, fork text,
  *           first_block int8, last_block int8)
@@ -203,7 +184,7 @@ pg_prewarm(PG_FUNCTION_ARGS)
    }
    else if (ptype == PREWARM_BUFFER)
    {
-       struct pg_prewarm_read_stream_private p;
+       BlockRangeReadStreamPrivate p;
        ReadStream *stream;
 
        /*
@@ -211,14 +192,14 @@ pg_prewarm(PG_FUNCTION_ARGS)
         */
 
        /* Set up the private state for our streaming buffer read callback. */
-       p.blocknum = first_block;
-       p.last_block = last_block;
+       p.current_blocknum = first_block;
+       p.last_exclusive = last_block + 1;
 
        stream = read_stream_begin_relation(READ_STREAM_FULL,
                                            NULL,
                                            rel,
                                            forkNumber,
-                                           pg_prewarm_read_stream_next_block,
+                                           block_range_read_stream_cb,
                                            &p,
                                            0);
 

diff --git a/src/backend/storage/aio/read_stream.c b/src/backend/storage/aio/read_stream.c
index 064861e5fb7a337c7deb8aa4ef0abb9465183ac3..039d3678114895f887c436b6f919cf96a1742de0 100644 (file)
--- a/src/backend/storage/aio/read_stream.c
+++ b/src/backend/storage/aio/read_stream.c
@@ -163,6 +163,23 @@ get_per_buffer_data(ReadStream *stream, int16 buffer_index)
        stream->per_buffer_data_size * buffer_index;
 }
 
+/*
+ * General-use ReadStreamBlockNumberCB for block range scans.  Loops over the
+ * blocks [current_blocknum, last_exclusive).
+ */
+BlockNumber
+block_range_read_stream_cb(ReadStream *stream,
+                          void *callback_private_data,
+                          void *per_buffer_data)
+{
+   BlockRangeReadStreamPrivate *p = callback_private_data;
+
+   if (p->current_blocknum < p->last_exclusive)
+       return p->current_blocknum++;
+
+   return InvalidBlockNumber;
+}
+
 /*
  * Ask the callback which block it would like us to read next, with a one block
  * buffer in front to allow read_stream_unget_block() to work.

diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 71d2ab8b49f6872ae710f473af7e30b3443a362d..485204430017eb3c3a4e0ea1333fe449e1a489f4 100644 (file)
--- 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);
 
    /* Initialize 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);
 

diff --git a/src/include/storage/read_stream.h b/src/include/storage/read_stream.h
index 42a623bfc540488384742c50ef0459774448d4b9..2f94ee744b951c3778eb23955bf89efc0e82b2bf 100644 (file)
--- a/src/include/storage/read_stream.h
+++ b/src/include/storage/read_stream.h
@@ -45,11 +45,21 @@
 struct ReadStream;
 typedef struct ReadStream ReadStream;
 
+/* for block_range_read_stream_cb */
+typedef struct BlockRangeReadStreamPrivate
+{
+   BlockNumber current_blocknum;
+   BlockNumber last_exclusive;
+} BlockRangeReadStreamPrivate;
+
 /* Callback that returns the next block number to read. */
 typedef BlockNumber (*ReadStreamBlockNumberCB) (ReadStream *stream,
                                                void *callback_private_data,
                                                void *per_buffer_data);
 
+extern BlockNumber block_range_read_stream_cb(ReadStream *stream,
+                                             void *callback_private_data,
+                                             void *per_buffer_data);
 extern ReadStream *read_stream_begin_relation(int flags,
                                              BufferAccessStrategy strategy,
                                              Relation rel,

diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9e951a9e6f30a8884c00bc4bd6483d25b4df60f2..df3f336bec0b77315d734a8634af0200cc6626a9 100644 (file)
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -275,6 +275,7 @@ BlockId
 BlockIdData
 BlockInfoRecord
 BlockNumber
+BlockRangeReadStreamPrivate
 BlockRefTable
 BlockRefTableBuffer
 BlockRefTableChunk