Horton

Re: [HACKERS] Moving relation extension locks out of heavyweight lock manager

Masahiko Sawada <sawada.mshk@gmail.com>

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From: Masahiko Sawada <sawada.mshk@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>, Andres Freund <andres@anarazel.de>, Mithun Cy <mithun.cy@enterprisedb.com>, Tom Lane <tgl@sss.pgh.pa.us>, Thomas Munro <thomas.munro@enterprisedb.com>, Amit Kapila <amit.kapila16@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-04-11T01:08:04Z
Lists: pgsql-hackers

Commits

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  1. Allow page lock to conflict among parallel group members.

  2. Allow relation extension lock to conflict among parallel group members.

  3. Add assert to ensure that page locks don't participate in deadlock cycle.

  4. Assert that we don't acquire a heavyweight lock on another object after

  5. Fix unsafe usage of strerror(errno) within ereport().

On Wed, Apr 11, 2018 at 1:40 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Tue, Apr 10, 2018 at 5:40 AM, Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>> The probability of performance degradation can be reduced by
>> increasing N_RELEXTLOCK_ENTS. But as Robert mentioned, while keeping
>> fast and simple implementation like acquiring lock by a few atomic
>> operation it's hard to improve or at least keep the current
>> performance on all cases. I was thinking that this patch is necessary
>> by parallel DML operations and vacuum but if the community cannot
>> accept this approach it might be better to mark it as "Rejected" and
>> then I should reconsider the design of parallel vacuum.
>
> I'm sorry that I didn't get time to work further on this during the
> CommitFest.

Never mind. There was a lot of items especially at the last CommitFest.

> In terms of moving forward, I'd still like to hear what
> Andres has to say about the comments I made on March 1st.

Yeah, agreed.

Regards,

--
Masahiko Sawada
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center