Hi, I'm trying to understand the relation between 'archive_mode', pg_wal directory, 'max_wal_size' and failover.
I'm running the kubernetes example from patroni (patroni 4.0.6) When 'archive_mode: off', and I issue a couple of 'patronictl failover' commands I observe the following files pg_wal: ``` postgres@patronidemo-0:~/pgdata/pgroot/data/pg_wal$ ls 000000080000000000000017 00000008.history 00000009.history 0000000A.history 0000000B.history 0000000C.history 000000080000000000000018 000000090000000000000018 0000000A0000000000000018 0000000B0000000000000018 0000000C0000000000000018 archive_status ``` Our problem with this is that If I do a lot of failovers, lets say a 100, then there will be a 100 files ( from 000000080000000000000018, to 0000001C0000000000000018) and during checkpoint it doesn't decrease, and can go way over max_wal_size. Whereas if I set 'archive_mode: on', and 'archive_command: /bin/true' ``` postgres@patronidemo-0:~/pgdata/pgroot/data/pg_wal$ ls 0000000E000000000000001F 0000000E.history 0000000F.history 00000010.history 00000011.history 0000000E0000000000000020 0000000F0000000000000021 000000100000000000000022 000000110000000000000023 archive_status 0000000E0000000000000021.partial 0000000F0000000000000022 000000100000000000000023.partial 000000110000000000000024 ``` In this latter case after a timeline id is incremented postgres creates a new file with an incremented seqno, and in this case the files get rotated out normally they don't go over max_wal_size Can someone explain why the difference in behavior? Does postgres only use the seqno only to differentiate the wal files here? Why does postgres not rotate out files in the former case? Many thanks, Arpi
