Horton

Re: Adding a TAP test checking data consistency on standby with minRecoveryPoint

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Andrew Gierth <andrew@tao11.riddles.org.uk>
Cc: Postgres hackers <pgsql-hackers@postgresql.org>
Date: 2018-11-08T05:25:48Z
Lists: pgsql-hackers 
On Thu, Nov 08, 2018 at 05:04:35AM +0000, Andrew Gierth wrote:
> How? It's OK (and normal) for in-core pages to have newer LSNs than
> minRecoveryPoint, it's only on-disk pages that must not be more recent
> than that. And pageinspect will show the in-core page...

If the standby is stopped cleanly once, what's in shared buffers gets
flushed to disk by the checkpointer once at shutdown, forcing
minRecoveryPoint to be updated by the checkpointer, and that update was
not happening beforethe fix.  And once the standby is started again,
what's on disk gets reloaded, showing the inconsistency.
--
Michael

Commits

  1. Add TAP test to check consistency of minimum recovery LSN