Re: A test for replay of regression tests

Hi,

On 2021-12-09 12:10:23 +1300, Thomas Munro wrote:
> From a60ada37f3ff7d311d56fe453b2abeadf0b350e5 Mon Sep 17 00:00:00 2001
> From: Thomas Munro <thomas(dot)munro(at)gmail(dot)com>
> Date: Wed, 4 Aug 2021 22:17:54 +1200
> Subject: [PATCH v8 2/5] Use relative paths for tablespace regression test.
>
> Remove the machinery from pg_regress that manages the testtablespace
> directory. Instead, use a relative path.
>
> Discussion: https://postgr.es/m/CA%2BhUKGKpRWQ9SxdxxDmTBCJoR0YnFpMBe7kyzY8SUQk%2BHeskxg%40mail.gmail.com

Seems like we ought to add a tiny tap test or such for this - otherwise we
won't have any coverage of "normal" tablespaces? I don't think they need to be
exercised as part of the normal tests, but having some very basic testing
in a tap test seems worthwhile.

> diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
> index 9467a199c8..5cfa137cde 100644
> --- a/src/test/perl/PostgreSQL/Test/Cluster.pm
> +++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
> @@ -460,7 +460,7 @@ sub init
> print $conf "hot_standby = on\n";
> # conservative settings to ensure we can run multiple postmasters:
> print $conf "shared_buffers = 1MB\n";
> - print $conf "max_connections = 10\n";
> + print $conf "max_connections = 25\n";
> # limit disk space consumption, too:
> print $conf "max_wal_size = 128MB\n";
> }

What's the relation of this to the rest?

> +# Perform a logical dump of primary and standby, and check that they match
> +command_ok(
> + [ "pg_dump", '-f', $outputdir . '/primary.dump', '--no-sync',
> + '-p', $node_primary->port, 'regression' ],
> + "dump primary server");
> +command_ok(
> + [ "pg_dump", '-f', $outputdir . '/standby.dump', '--no-sync',
> + '-p', $node_standby_1->port, 'regression' ],
> + "dump standby server");
> +command_ok(
> + [ "diff", $outputdir . '/primary.dump', $outputdir . '/standby.dump' ],
> + "compare primary and standby dumps");
> +

Absurd nitpick: What's the deal with using "" for one part, and '' for the
rest?

Separately: I think the case of seeing diffs will be too hard to debug like
this, as the difference isn't shown afaict?

Greetings,

Andres Freund