Re: Add basic tests for the low-level backup method.

On Thu, Feb 29, 2024 at 10:30:52AM +1300, David Steele wrote:
> On 11/12/23 08:21, David Steele wrote:
>> As promised in [1], attached are some basic tests for the low-level
>> backup method.
> 
> Added to the 2024-03 CF.

There is already 040_standby_failover_slots_sync.pl in recovery/ that
uses the number of your test script.  You may want to bump it, that's
a nit.

+unlink("$backup_dir/postmaster.pid")
+	or BAIL_OUT("unable to unlink $backup_dir/postmaster.pid");
+unlink("$backup_dir/postmaster.opts")
+	or BAIL_OUT("unable to unlink $backup_dir/postmaster.opts");
+unlink("$backup_dir/global/pg_control")
+	or BAIL_OUT("unable to unlink $backup_dir/global/pg_control");

RELCACHE_INIT_FILENAME as well?

+# Rather than writing out backup_label, try to recover the backup without
+# backup_label to demonstrate that recovery will not work correctly without it,
+# i.e. the canary table will be missing and the cluster will be corrupt. Provide
+# only the WAL segment that recovery will think it needs.

Okay, why not.  No objections to this addition.  I am a bit surprised
that this is not scanning some of the logs produced by the startup
process for particular patterns.

+# Save backup_label into the backup directory and recover using the primary's
+# archive. This time recovery will succeed and the canary table will be
+# present. 

Here are well, I think that we should add some log_contains() with
pre-defined patterns to show that recovery has completed the way we
want it with a backup_label up to the end-of-backup record.
--
Michael