From 14ff44f80c09718d43d853363941457f5468cc03 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Thu, 22 Sep 2022 09:47:28 +0900 Subject: Used optimized linear search in more code paths This commit updates two code paths to use pg_lfind32() introduced by b6ef167 with TransactionId arrays: - At the end of TransactionIdIsInProgress(), when checking for the case of still running but overflowed subxids. - XidIsConcurrent(), when checking for a serializable conflict. These cases are less impactful than 37a6e5d, but a bit of micro-benchmarking of this API shows that linear search speeds up by ~20% depending on the number of items involved (x86_64 and amd64 looked at here). Author: Nathan Bossart Reviewed-by: Richard Guo, Michael Paquier Discussion: https://postgr.es/m/20220901185153.GA783106@nathanxps13 --- src/backend/storage/ipc/procarray.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'src/backend/storage/ipc') diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c index 382f4cfb736..207c4b27fdf 100644 --- a/src/backend/storage/ipc/procarray.c +++ b/src/backend/storage/ipc/procarray.c @@ -58,6 +58,7 @@ #include "commands/dbcommands.h" #include "miscadmin.h" #include "pgstat.h" +#include "port/pg_lfind.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/spin.h" @@ -1586,14 +1587,9 @@ TransactionIdIsInProgress(TransactionId xid) */ topxid = SubTransGetTopmostTransaction(xid); Assert(TransactionIdIsValid(topxid)); - if (!TransactionIdEquals(topxid, xid)) - { - for (int i = 0; i < nxids; i++) - { - if (TransactionIdEquals(xids[i], topxid)) - return true; - } - } + if (!TransactionIdEquals(topxid, xid) && + pg_lfind32(topxid, xids, nxids)) + return true; cachedXidIsNotInProgress = xid; return false; -- cgit v1.2.3