Horton

Re: inefficient loop in StandbyReleaseLockList()

Kyotaro Horiguchi <horikyota.ntt@gmail.com>

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From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
To: bossartn@amazon.com
Cc: tgl@sss.pgh.pa.us, michael@paquier.xyz, andres@anarazel.de, sulamul@gmail.com, pgsql-hackers@postgresql.org
Date: 2021-11-02T00:58:16Z
Lists: pgsql-hackers 
At Mon, 1 Nov 2021 17:02:49 +0000, "Bossart, Nathan" <bossartn@amazon.com> wrote in 
> On 11/1/21, 9:58 AM, "Tom Lane" <tgl@sss.pgh.pa.us> wrote:
> > "Bossart, Nathan" <bossartn@amazon.com> writes:
> >> Should there be a list_free(trgmNFA->queue) at the end of
> >> transformGraph()?
> >
> > There could be, but that's visibly invoked only once per
> > createTrgmNFAInternal call, so I didn't think it was worthwhile
> > to do so (unlike the case for processState).  If we were concerned
> > about leakage in that function, the hash table would be a far
> > bigger issue.
> 
> Ah, I see it now.  The patch looks good to me, then.

+1

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

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.