Horton

Re: Replication slot stats misgivings

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: vignesh C <vignesh21@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Date: 2021-05-12T04:49:11Z
Lists: pgsql-hackers 
vignesh C <vignesh21@gmail.com> writes:
> On Wed, May 12, 2021 at 9:59 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Is there any value in converting the test case into a TAP test that
>> could be more flexible about the expected output?  I'm mainly wondering
>> whether there are any code paths that this test forces the server through,
>> which would otherwise lack coverage.

> Removing this test does not reduce code coverage. This test is
> basically to decode and check the stats again, it is kind of a
> repetitive test. The problem with this test here is that when a
> transaction is spilled, the statistics for the spill transaction will
> be sent to the statistics collector as and when the transaction is
> spilled. This test sends spill stats around 12 times. The test expects
> to reset the stats and check the stats gets updated when we get the
> changes. We cannot validate reset slot stats results here, as it could
> be possible that in some machines the stats collector receives the
> spilled transaction stats after getting reset slots. This same problem
> will exist with tap tests too. So I feel it is better to remove this
> test.

OK, I'm satisfied as long as we've considered the code-coverage angle.

			regards, tom lane

Commits

  1. Doc: Update logical decoding stats information.

  2. Fix tests for replication slots stats.

  3. Update replication statistics after every stream/spill.

  4. Fix the computation of slot stats for 'total_bytes'.

  5. Another try to fix the test case added by commit f5fc2f5b23.

  6. Use HTAB for replication slot statistics.

  7. Fix test case added by commit f5fc2f5b23.

  8. Add information of total data processed to replication slot stats.

  9. Use NameData datatype for slotname in stats.