At Tue, 27 Jul 2021 07:50:39 +0200, Ronan Dunklau <ronan.dunk...@aiven.io> wrote in > Hello, > > I've notived that pg_receivewal logic for deciding which LSN to start > streaming at consists of: > - looking up the latest WAL file in our destination folder, and resume from > here > - if there isn't, use the current flush location instead. > > This behaviour surprised me when using it with a replication slot: I was > expecting it to start streaming at the last flushed location from the > replication slot instead. If you consider a backup tool which will take > pg_receivewal's output and transfer it somewhere else, using the replication > slot position would be the easiest way to ensure we don't miss WAL files. > > Does that make sense ? > > I don't know if it should be the default, toggled by a command line flag, or > if > we even should let the user provide a LSN.
*I* think it is completely reasonable (or at least convenient or less astonishing) that pg_receivewal starts from the restart_lsn of the replication slot to use. The tool already decides the clean-start LSN a bit unusual way. And it seems to me that proposed behavior can be the default when -S is specified. > I'd be happy to implement any of that if we agree. regards. -- Kyotaro Horiguchi NTT Open Source Software Center
