On 2020/07/28 9:08, Ayub M wrote: > I have a RDS PostgreSQL v11.6 with primary and standby. On the primary, vacuum/analyze > were running and pg_stat_all_tables's last_vacuum/analyze/autovacuum/autoanalyze > were having values when vacuum/analyze were run. > > 1. Switchover to Standby happened, now when I see pg_stat_all_tables (on the active > primary which was standby earlier), the last vacuum/analyze columns are all nulls. > Would primary-standby replication not replicate system tables? Is this how it behaves?
The information shown by the various pg_stat_* views is specific to the local server, and is *not* replicated. In most cases that wouldn't even make sense. The information is collated by the statistics collector [1] and is stored in memory and/or files in the data directory, not as a system table. [1] https://www.postgresql.org/docs/current/monitoring-stats.html > 2. On the new primary, would the table have stats on them? (I do see pg_stats > entries for the tables on new standby), are they reliable or do I need to gather > stats and run vacuum after failover/switchover to standby? The statistics about the *contents* of the database, as shown by pg_stats, are of course replicated and will be reliable. More precisely they'll be as up-to-date as the last vacuum/analyze on the former primary, just you won't see the information about when that was. Regards Ian Barwick -- Ian Barwick https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
