On Thu, Jun 27, 2024 at 5:56 PM Paul Jungwirth <p...@illuminatedcomputing.com> wrote: > I did add a relperiods column, but I have a mostly-complete branch here (not > included in the > patches) that does without. Not maintaining that new column is simpler for > sure. The consequence is > that the relcache must scan for WITHOUT OVERLAPS constraints on every table. > That seems like a high > performance cost for a feature most databases won't use. Since we try hard to > avoid that kind of > thing (e.g. [1]), I thought adding relperiods would be preferred. If that's > the wrong tradeoff I can > change it.
I'm sure that you are right that nobody is going to like an extra index scan just to find periods. So, suppose we do as you propose and add relperiods. In the situation where we are adding the first period (or whatever the right term is) to the table, what kind of lock are we holding on the table? Conversely, when we drop the last period, what kind of lock are we holding on the table? If, hypothetically, both answers were AccessExclusiveLock, this might not be too bad, but if you say "ShareLock" then we've got a lot of problems; that's not even self-exclusive. > These patches still add some if-clauses to psql and pg_dump that say `if > (fout->remoteVersion >= > 170000)`. But if I change them to 180000 I get failures in e.g. the pg_dump > tests. What do other > people do here before a release is cut? Sometimes I make a commit that bumps the version number (update major version in src/tools/version_stamp.pl, then run it, then run autoconf, then commit). Then I build my patch set on top of that. Once the actual major release bump happens, I just drop that commit from the stack. -- Robert Haas EDB: http://www.enterprisedb.com
