Horton

Re: Creating a function for exposing memory usage of backend process

Michael Paquier <michael@paquier.xyz>

View thread View on postgr.es
From: Michael Paquier <michael@paquier.xyz>
To: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: torikoshia <torikoshia@oss.nttdata.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>, Kasahara Tatsuhito <kasahara.tatsuhito@gmail.com>, Andres Freund <andres@anarazel.de>
Date: 2020-08-19T13:55:45Z
Lists: pgsql-hackers 
On Wed, Aug 19, 2020 at 06:12:02PM +0900, Fujii Masao wrote:
> On 2020/08/19 17:40, torikoshia wrote:
>> Yes, I didn't add regression tests because of the unstability of the output.
>> I thought it would be OK since other views like pg_stat_slru and pg_shmem_allocations
>> didn't have tests for their outputs.
> 
> You're right.

If you can make a test with something minimal and with a stable
output, adding a test is helpful IMO, or how can you make easily sure
that this does not get broken, particularly in the event of future
refactorings, or even with platform-dependent behaviors?

By the way, I was looking at the code that has been committed, and I
think that it is awkward to have a SQL function in mcxt.c, which is a
rather low-level interface.  I think that this new code should be
moved to its own file, one suggestion for a location I have being
src/backend/utils/adt/mcxtfuncs.c.
--
Michael

Commits

  1. Add regression test for pg_backend_memory_contexts.

  2. Move codes for pg_backend_memory_contexts from mmgr/mcxt.c to adt/mcxtfuncs.c.

  3. Prevent non-superusers from reading pg_backend_memory_contexts, by default.

  4. Add pg_backend_memory_contexts system view.

  5. Fix yet another issue with step generation in partition pruning.