On Thu, Aug 6, 2020 at 7:02 AM Sreejith P <sreejith@xxxxxxxxxxxxx> wrote: > IN SYNC mode of replication what would be the impact on Master DB server in terms of over all performance ? The pg_stat_replication columns write_lag, flush_lag and replay_lag are designed tell you how long to expect commits to take for synchronous standbys, based on recent history, if synchronous_commit it set to remote_write, on or remote_apply respectively. Those times tell you about commit latency, which limits sequential commit rate for each session.
