OK, As mentioned in the previous message, I've reverted most of 39b66a91bd. It took a bit longer to test, because the revert patch I shared a couple days ago was actually incorrect/buggy in one place.
I'm not entirely happy about the end result (as it does not really help with TOAST tables), so hopefully we'll be able to do something about that soon. I'm not sure what, though - we've spent quite a bit of time trying to address the regression, and I don't envision some major breakthrough. As for the regression example, I think in practice the impact would be much lower, because the queries are likely much more complex (not just a seqscan from a table), so the query execution will be a much bigger part of execution time. I do think the optimization would be a win in most cases where freezing is desirable. From this POV the problem is rather that REFRESH MV does not allow not freezing the result, so it has to pay the price always. So perhaps the way forward is to add "NO FREEZE" option to REFRESH MV, or something like that. regards -- Tomas Vondra EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
