On Tue, May 16, 2023 at 04:23:02PM +0200, hubert depesz lubaczewski wrote: > Hi, > I'm working on a workaround for a bug in Pg > (https://www.postgresql.org/message-id/flat/Yz2hivgyjS1RfMKs%40depesz.com) > I want to create replication slot, and advance is manually, keeping it > always a bit lagging behind real replication slot. > > I can create slot, no problem: > select pg_create_logical_replication_slot('depesz', 'test_decoding'); > and then I can, theoretically, advance it to whatever position with > select * from pg_replication_slot_advance('depesz', '...'); > > *BUT* - it changes only confirmed_flush_lsn, leaving restart_lsn as it > was. > > How can I advance restart_lsn of a slot? > > Generally my idea is to get lsn from real replication slot, subtract, > let's say 1GB from it, and advance my "fake slot" to this value, this > keeping always buffer of 1GB in case the bug with removed wal happened > again. > > I will be doing this on Pg12, which can limit my options, but perhaps > there is some way to do it via plain(ish) SQL ? Hi, if doing it via SQL is not an option, is there any way to have replication slot and modify it's restart_lsn, regardless of whether it will b e physical, or logical, and what tool shoudl I use. I tried with pg_recvlogical, and read https://www.postgresql.org/docs/current/protocol-replication.html but I don't see how I can make restart_lsn advance to anything. Best regards, depesz
