Re: Moving relation extension locks out of heavyweight lock manager

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>

To: Masahiko Sawada <sawada.mshk@gmail.com>

Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>

Date: 2017-05-13T11:19:52Z

Lists: pgsql-hackers

Commits

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Allow page lock to conflict among parallel group members.
- 3ba59ccc896e 13.0 landed
Allow relation extension lock to conflict among parallel group members.
- 85f6b49c2c53 13.0 landed
Add assert to ensure that page locks don't participate in deadlock cycle.
- 72e78d831ab5 13.0 landed
Assert that we don't acquire a heavyweight lock on another object after
- 15ef6ff4b985 13.0 landed
Fix unsafe usage of strerror(errno) within ereport().
- 81256cd05f07 11.0 cited

On Thu, May 11, 2017 at 6:09 AM, Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> This work would be helpful not only for existing workload but also
> future works like some parallel utility commands, which is discussed
> on other threads[1]. At least for parallel vacuum, this feature helps
> to solve issue that the implementation of parallel vacuum has.
>
> I ran pgbench for 10 min three times(scale factor is 5000), here is a
> performance measurement result.
>
> clients   TPS(HEAD)   TPS(Patched)
> 4           2092.612       2031.277
> 8           3153.732       3046.789
> 16         4562.072       4625.419
> 32         6439.391       6479.526
> 64         7767.364       7779.636
> 100       7917.173       7906.567
>
> * 16 core Xeon E5620 2.4GHz
> * 32 GB RAM
> * ioDrive
>
> In current implementation, it seems there is no performance degradation so far.
>

I think it is good to check pgbench, but we should do tests of the
bulk load as this lock is stressed during such a workload.  Some of
the tests we have done when we have improved the performance of bulk
load can be found in an e-mail [1].

[1] -
https://www.postgresql.org/message-id/CAFiTN-tkX6gs-jL8VrPxg6OG9VUAKnObUq7r7pWQqASzdF5OwA%40mail.gmail.com

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