Hi.
Some (maybe all) row statistics are lost after the database has
recovered after a failover. So it's recommended to ANALYZE all databases
in a cluster after recovery.
Amazon's AWS RDS (their managed SQL databases service) even sends an
email "consider running analyze if your database is slow" after a
failover of so called MultiAZ databases (with fast automatic failover
for double price). Funny that they send it for both PostgreSQL and
Oracle databases, which, I suppose, confuses Oracle DBA's greatly.
And in AWS RDS MultiAZ a failover is pretty common. Minor version
upgrade - failover. A storage hiccup - failover. Out of memory - failover.
Shouldn't this analyze be queued and all tables analyzed automatically
after failover by autovacuum daemon? With up to autovacuum_max_workers
in parallel?
It might save some DBA's from a couple of lost sleeping hours for sure.
What do you think? A GUC option? On by dafault? Maybe even backported,
but off by default in released versions?
--
Tomasz "Tometzky" Ostrowski
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