On Thu, Dec 5, 2024, at 6:43 AM, Jakub Wartak wrote: > One of our customers ran into a very odd case, where hot standby feedback > backend_xmin propagation stopped working due to major (hours/days) clock time > shifts on hypervisor-managed VMs. This happens (and is fully reproducible) > e.g. in scenarios where standby connects and its own VM is having time from > the future (relative to primary) and then that time goes back to "normal". In > such situation "sends hot_standby_feedback xmin" timestamp messages are > stopped being transferred, e.g.:
Is it worth a WARNING message if there is a "huge" time difference between the servers? We already have the reply time in the message so it is a matter of defining the "huge" interval plus a roundtrip. We also need to avoid spamming the log. Your patch looks good to me. Should it be converted into a <note>...</note>? (See synchronous_standby_names [1] for an example.) [1] https://www.postgresql.org/docs/current/runtime-config-replication.html -- Euler Taveira EDB https://www.enterprisedb.com/
