On Tue, Jan 7, 2020 at 12:47 PM David Fetter <da...@fetter.org> wrote: > Per a suggestion Christophe made, please find attached a patch to > $Subject:
Curious, what's the benefit of autovacuum handling the oldest tables first? If there is a related thread with the discussion, I couldn't find it. > Apart from carefully fudging with pg_resetwal, and short of running in > production for a few weeks, what would be some good ways to test this? Greenplum tests autovacuum using a fault injection framework, which was once proposed by Asim [1] and a function to consume xids [2]. If that isn't an option, maybe you could acquire a vacuum blocking lock on a table, for example by creating index on it inside a dangling transaction. Then after autovacuum worker blocks, in a separate session you could check that a previously older table is now younger. Does that suffice? Thanks, David [1] https://www.postgresql.org/message-id/CANXE4TdxdESX1jKw48xet-5GvBFVSq=4cgneiotqff372ko...@mail.gmail.com [2] https://github.com/greenplum-db/gpdb/blob/5feccaae6838e68b1443e46ed39d162613c5ece8/src/test/regress/regress_gp.c#L2003
