Horton

Re: inefficient loop in StandbyReleaseLockList()

Nathan Bossart <bossartn@amazon.com>

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From: "Bossart, Nathan" <bossartn@amazon.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>, "michael@paquier.xyz" <michael@paquier.xyz>, "andres@anarazel.de" <andres@anarazel.de>, "sulamul@gmail.com" <sulamul@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2021-11-02T15:39:38Z
Lists: pgsql-hackers 
On 11/2/21, 8:36 AM, "Tom Lane" <tgl@sss.pgh.pa.us> wrote:
> I've pushed the SyncPostCheckpoint change, and I think I'm going
> to stop here.  It's not clear that the remaining list_delete_first
> callers have any real problem; and changing them would be complex.
> We can revisit the question if we find out there is an issue.
> Or, if somebody else wants to pursue the issue, feel free.

Thanks!

Nathan

Commits

  1. Doc: add some notes about performance of the List functions.

  2. Avoid O(N^2) behavior in SyncPostCheckpoint().

  3. Avoid some other O(N^2) hazards in list manipulation.

  4. Avoid O(N^2) behavior when the standby process releases many locks.