Re: Minimal logical decoding on standbys

On Mon, Sep 30, 2019 at 7:35 AM Amit Khandekar <amitdkhan(dot)pg(at)gmail(dot)com> wrote:
> Alright. Attached is the updated patch that splits the file into two
> files, one that does only xmin related testing, and the other test
> file that tests conflict recovery scenarios, and also one scenario
> where drop-database drops the slots on the database on standby.
> Removed get_slot_xmins() and get_node_from_slotname().
> Renamed 'replica' to 'standby'.
> Used node->backup() function instead of pg_basebackup command.
> Renamed $master_slot to $master_slotname, similarly for $standby_slot.

In general, I think this code is getting a lot clearer and easier to
understand in these last few revisions.

Why does create_logical_slot_on_standby include sleep(1)? Does the
test fail if you take that out? If so, it's probably going to fail on
the buildfarm even with that included, because some of the buildfarm
machines are really slow (e.g. because they use CLOBBER_CACHE_ALWAYS,
or because they're running on a shared system with low hardware
specifications and an ancient disk).

Similarly for the sleep(1) just after you VACUUM FREEZE all the databases.

I'm not sure wait the point of the wait_for_xmins() stuff is in
019_standby_logical_decoding_conflicts.pl. Isn't that just duplicating
stuff we've already tested in 018?

--
Robert Haas
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