From 597125e124b3d92ef3a0ca243722aa0f99238037 Mon Sep 17 00:00:00 2001 From: Matthias van de Meent Date: Wed, 11 Dec 2024 01:51:05 +0100 Subject: [PATCH] Disable readstream's reliance on seqscan readahead (#9860) Neon doesn't have seqscan detection of its own, so stop read_stream from trying to utilize that readahead, and instead make it issue readahead of its own. ## Problem @knizhnik noticed that we didn't issue smgrprefetch[v] calls for seqscans in PG17 due to the move to the read_stream API, which assumes that the underlying IO facilities do seqscan detection for readahead. That is a wrong assumption when Neon is involved, so let's remove the code that applies that assumption. ## Summary of changes Remove the cases where seqscans are detected and prefetch is disabled as a consequence, and instead don't do that detection. PG PR: https://github.com/neondatabase/postgres/pull/532 --- vendor/postgres-v17 | 2 +- vendor/revisions.json | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/vendor/postgres-v17 b/vendor/postgres-v17 index 471c449ab8..01fa3c4866 160000 --- a/vendor/postgres-v17 +++ b/vendor/postgres-v17 @@ -1 +1 @@ -Subproject commit 471c449ab8f8ff5988b6bfb9eafa0a79772ad562 +Subproject commit 01fa3c48664ca030cfb69bb4a350aa9df4691d88 diff --git a/vendor/revisions.json b/vendor/revisions.json index ba0f34e23e..7329aa437f 100644 --- a/vendor/revisions.json +++ b/vendor/revisions.json @@ -1,7 +1,7 @@ { "v17": [ "17.2", - "471c449ab8f8ff5988b6bfb9eafa0a79772ad562" + "01fa3c48664ca030cfb69bb4a350aa9df4691d88" ], "v16": [ "16.6",