Robert Haas <robertmh...@gmail.com> writes: > On Wed, Nov 29, 2017 at 11:17 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> The thing that makes me uncomfortable about this is that we used to have a >> catcache size limitation mechanism, and ripped it out because it had too >> much overhead (see commit 8b9bc234a). I'm not sure how we can avoid that >> problem within a fresh implementation.
> At the risk of beating a dead horse, I still think that the amount of > wall clock time that has elapsed since an entry was last accessed is > very relevant. While I don't object to that statement, I'm not sure how it helps us here. If we couldn't afford DLMoveToFront(), doing a gettimeofday() during each syscache access is surely right out. regards, tom lane