Horton

Re: Two pg_rewind patches (auto generate recovery conf and ensure clean shutdown)

Paul Guo <pguo@pivotal.io>

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From: Paul Guo <pguo@pivotal.io>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Michael Paquier <michael@paquier.xyz>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>, Jimmy Yih <jyih@pivotal.io>, Ashwin Agrawal <aagrawal@pivotal.io>
Date: 2019-07-02T05:54:45Z
Lists: pgsql-hackers 
On Tue, Jul 2, 2019 at 12:35 AM Alvaro Herrera <alvherre@2ndquadrant.com>
wrote:

> On 2019-Apr-19, Paul Guo wrote:
>
> > The below patch runs single mode Postgres if needed to make sure the
> target
> > is cleanly shutdown. A new option is added (off by default).
> > v2-0001-Ensure-target-clean-shutdown-at-beginning-of-pg_r.patch
>
> Why do we need an option for this?  Is there a reason not to do this
> unconditionally?
>

There is concern about this (see previous emails in this thread). On
greenplum (MPP DB based on Postgres),
we unconditionally do this. I'm not sure about usually how Postgres users
do this when there is an unclean shutdown,
but providing an option seem to be safer to avoid breaking existing
script/service whatever. If many people
think this option is unnecessary, I'm fine to remove the option and keep
the code logic.

Commits

  1. Improve test coverage of pg_rewind

  2. Improve handling and coverage of --no-ensure-shutdown in pg_rewind

  3. Fix issues in pg_rewind with --no-ensure-shutdown/--write-recovery-conf

  4. Fix --dry-run mode of pg_rewind

  5. pg_rewind: test new --write-recovery-conf functionality

  6. pg_rewind: Allow writing recovery configuration

  7. Have pg_rewind run crash recovery before rewinding

  8. Split out recovery confing-writing code from pg_basebackup

  9. Switch TAP tests of pg_rewind to use non-superuser role, take two