Hi hackers!
In our Cloud we have a patch, which allows non-superuser role ('mdb_admin')
to do some superuser things.
In particular, we have a patch that allows mdb admin to cancel the
autovacuum process and some other processes (processes with
application_name = 'MDB'), see the attachment.
This is needed to allow non-superuser roles to run pg_repack and to cancel
pg_repack.
We need to cancel running autovac to run pg_repack (because of locks), and
we need to cancel pg_repack sometimes also.I want to reduce our internal patch size and transfer this logic to extension or to core. I have found similar threads [1] and [2], but, as far as I understand, they do not solve this particular case. I see 2 possible ways to implement this. The first one is to have hool in pg_signal_backend, and define a hook in extension which can do the thing. The second one is to have a predefined role. Something like a `pg_signal_autovacuum` role which can signal running autovac to cancel. But I don't see how we can handle specific `application_name` with this solution. [1] https://www.postgresql.org/message-id/flat/F9408A5A-B20B-42D2-9E7F-49CD3D1547BC%40enterprisedb.com [2] https://www.postgresql.org/message-id/flat/20220722203735.GB3996698%40nathanxps13
v1-0001-cloud-mdb_admin-patch-part-to-illustrate.patch
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