Horton

Re: O(n^2) system calls in RemoveOldXlogFiles()

Michael Paquier <michael@paquier.xyz>

View thread View on postgr.es
From: Michael Paquier <michael@paquier.xyz>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-01-15T02:42:50Z
Lists: pgsql-hackers 
On Fri, Jan 15, 2021 at 03:25:24PM +1300, Thomas Munro wrote:
> Thanks Michael!  Another notch for the unnecessary system call
> hitlist: https://wiki.postgresql.org/wiki/Syscall_Reduction

A quick question.  How much does it matter in terms of
micro-performance for this code path depending on max/min_wal_size?
Andres has mentioned its aio work, without telling any numbers.
--
Michael

Commits

  1. Fix O(N^2) stat() calls when recycling WAL segments