Horton

Re: Combine pg_walinspect till_end_of_wal functions with others

Matthias van de Meent <boekewurm+postgres@gmail.com>

View thread View on postgr.es
From: Matthias van de Meent <boekewurm+postgres@gmail.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Julien Rouhaud <rjuju123@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Michael Paquier <michael@paquier.xyz>
Date: 2023-03-06T15:21:47Z
Lists: pgsql-hackers 
On Mon, 6 Mar 2023 at 16:06, Bharath Rupireddy
<bharath.rupireddyforpostgres@gmail.com> wrote:
> If we try to make these functions figure out the oldest WAl file and
> start from there, then it'll unnecessarily complicate the APIs and
> functions. If we still think we need a better function for the users
> to figure out the oldest WAL file, perhaps, add a SQL-only
> view/function to pg_walinspect that returns "select name from
> pg_ls_waldir() order by name limit 1;", but honestly, that's so
> trivial.

That "order by name limit 1" has subtle bugs when you're working on a
system that has experienced timeline switches. It is entirely possible
that the first file (as sorted by the default collation) is not the
first record you can inspect, or even in your timeline's history.


Kind regards,

Matthias van de Meent

Commits

  1. Improve a bit the tests of pg_walinspect

  2. Tweak regression test of pg_walinspect to be less collation-sensitive

  3. Rework design of functions in pg_walinspect

  4. Refactor and improve tests of pg_walinspect

  5. doc: Fix description of pg_get_wal_stats_till_end_of_wal() in pg_walinspect