Hi, On 2023-05-22 12:15:07 +0000, Zhijie Hou (Fujitsu) wrote: > About "a backend doing logical decoding", do you mean the case when a user > start a backend and invoke pg_logical_slot_get_changes() to do the logical > decoding ? If so, it seems the logical decoding in a backend won't be waked up > by startup process because the backend won't be registered as a walsender so > the backend won't be found in WalSndWakeup().
I meant logical decoding happening inside a walsender instance. > Or do you mean the deadlock between the real logical walsender and startup > process ? (I might miss something) I think the logical decoding doesn't lock > the target user relation when decoding because it normally can get the needed > information from WAL. It does lock catalog tables briefly. There's no guarantee that such locks are released immediately. I forgot the details, but IIRC there's some outfuncs (enum?) that intentionally delay releasing locks till transaction commit. Greetings, Andres Freund
