Horton

Re: Moving relation extension locks out of heavyweight lock manager

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-05-13T11:27:45Z
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 Fri, May 12, 2017 at 9:14 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> On Wed, May 10, 2017 at 8:39 PM, Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>>> ... I'd like to propose to change relation
>>> extension lock management so that it works using LWLock instead.
>
>> That's not a good idea because it'll make the code that executes while
>> holding that lock noninterruptible.
>
> Is that really a problem?  We typically only hold it over one kernel call,
> which ought to be noninterruptible anyway.
>

During parallel bulk load operations, I think we hold it over multiple
kernel calls.

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com