diff options
Diffstat (limited to 'src/backend/storage/aio/read_stream.c')
| -rw-r--r-- | src/backend/storage/aio/read_stream.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/src/backend/storage/aio/read_stream.c b/src/backend/storage/aio/read_stream.c index 26e5dfe77db..36c54fb695b 100644 --- a/src/backend/storage/aio/read_stream.c +++ b/src/backend/storage/aio/read_stream.c @@ -102,6 +102,7 @@ struct ReadStream int16 initialized_buffers; int read_buffers_flags; bool sync_mode; /* using io_method=sync */ + bool batch_mode; /* READ_STREAM_USE_BATCHING */ bool advice_enabled; bool temporary; @@ -403,6 +404,15 @@ read_stream_start_pending_read(ReadStream *stream) static void read_stream_look_ahead(ReadStream *stream) { + /* + * Allow amortizing the cost of submitting IO over multiple IOs. This + * requires that we don't do any operations that could lead to a deadlock + * with staged-but-unsubmitted IO. The callback needs to opt-in to being + * careful. + */ + if (stream->batch_mode) + pgaio_enter_batchmode(); + while (stream->ios_in_progress < stream->max_ios && stream->pinned_buffers + stream->pending_read_nblocks < stream->distance) { @@ -450,6 +460,8 @@ read_stream_look_ahead(ReadStream *stream) { /* We've hit the buffer or I/O limit. Rewind and stop here. */ read_stream_unget_block(stream, blocknum); + if (stream->batch_mode) + pgaio_exit_batchmode(); return; } } @@ -484,6 +496,9 @@ read_stream_look_ahead(ReadStream *stream) * time. */ Assert(stream->pinned_buffers > 0 || stream->distance == 0); + + if (stream->batch_mode) + pgaio_exit_batchmode(); } /* @@ -617,6 +632,7 @@ read_stream_begin_impl(int flags, MAXALIGN(&stream->ios[Max(1, max_ios)]); stream->sync_mode = io_method == IOMETHOD_SYNC; + stream->batch_mode = flags & READ_STREAM_USE_BATCHING; #ifdef USE_PREFETCH |