cefb82d49e
In b07642dbc, we added code to trigger autovacuums based on the number of INSERTs into a table. This seems to have cause some destabilization of the regression tests. Likely this is due to an autovacuum triggering mid-test and (per theory from Tom Lane) one of the test's queries causes autovacuum to skip some number of pages, resulting in the reltuples estimate changing. The failure that this is attempting to fix is around the order of subnodes in an Append. Since the planner orders these according to the subnode cost, then it's possible that a small change in the reltuples value changes the subnode's cost enough that it swaps position with one of its fellow subnodes. The failure here only seems to occur on slower buildfarm machines. In this case, lousyjack, which seems have taken over 8 minutes to run just the partitionwise_aggregate test. Such a slow run would increase the chances that the autovacuum launcher would trigger a vacuum mid-test. Faster machines run this test in sub second time, so have a much smaller window for an autovacuum to trigger. Here we fix this by disabling autovacuum on all tables created in the test. Additionally, this reverts the change made in the partitionwise_aggregate test in 2dc16efed. Discussion: https://postgr.es/m/22297.1585797192@sss.pgh.pa.us
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