From db05a33e742cb292b1a2d44665582042fcd05d2f Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Tue, 10 Sep 2024 10:15:33 +1200 Subject: [PATCH] Allow raw block numbers to be read from ReadStream. --- src/backend/storage/aio/read_stream.c | 14 ++++++++++++++ src/include/storage/read_stream.h | 3 +++ 2 files changed, 17 insertions(+) diff --git a/src/backend/storage/aio/read_stream.c b/src/backend/storage/aio/read_stream.c index 7f0e07d9586..cf914a7712f 100644 --- a/src/backend/storage/aio/read_stream.c +++ b/src/backend/storage/aio/read_stream.c @@ -835,3 +835,17 @@ read_stream_end(ReadStream *stream) read_stream_reset(stream); pfree(stream); } + +/* + * Transitional support for code that would like to perform a read directly, + * without using the stream. Returns, and skips, the next block number that + * would be read by the stream's look-ahead algorithm, or InvalidBlockNumber + * if the end of the stream is reached. Also reports the strategy that would + * be used to read it. + */ +BlockNumber +read_stream_next_block(ReadStream *stream, BufferAccessStrategy *strategy) +{ + *strategy = stream->ios[0].op.strategy; + return read_stream_get_block(stream, NULL); +} diff --git a/src/include/storage/read_stream.h b/src/include/storage/read_stream.h index 2f94ee744b9..37b51934f8d 100644 --- a/src/include/storage/read_stream.h +++ b/src/include/storage/read_stream.h @@ -68,6 +68,9 @@ extern ReadStream *read_stream_begin_relation(int flags, void *callback_private_data, size_t per_buffer_data_size); extern Buffer read_stream_next_buffer(ReadStream *stream, void **per_buffer_data); +extern BlockNumber read_stream_next_block(ReadStream *stream, + BufferAccessStrategy *strategy); + extern ReadStream *read_stream_begin_smgr_relation(int flags, BufferAccessStrategy strategy, SMgrRelation smgr, -- 2.46.0