From 51cb522b6b2467c63268d4c7f37af07914b081c6 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Tue, 18 Mar 2025 14:40:06 -0400 Subject: [PATCH v2.15 15/18] Temporary: Increase BAS_BULKREAD size Without this we only can execute very little AIO for sequential scans, as there's just not enough buffers in the ring. This isn't the right fix, as just increasing the ring size can have negative performance implications in workloads where the kernel has all the data cached. Author: Reviewed-By: Discussion: https://postgr.es/m/ Backpatch: --- src/backend/storage/buffer/freelist.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/backend/storage/buffer/freelist.c b/src/backend/storage/buffer/freelist.c index 336715b6c63..b72a5957a20 100644 --- a/src/backend/storage/buffer/freelist.c +++ b/src/backend/storage/buffer/freelist.c @@ -555,7 +555,12 @@ GetAccessStrategy(BufferAccessStrategyType btype) return NULL; case BAS_BULKREAD: - ring_size_kb = 256; + + /* + * FIXME: Temporary increase to allow large enough streaming reads + * to actually benefit from AIO. This needs a better solution. + */ + ring_size_kb = 2 * 1024; break; case BAS_BULKWRITE: ring_size_kb = 16 * 1024; -- 2.48.1.76.g4e746b1a31.dirty