On Sun, Mar 25, 2018 at 02:28:29PM -0400, Tom Lane wrote: > Arthur Zakirov <a.zaki...@postgrespro.ru> writes: > > If all dictionaries will be shareable then this view could be removed. > > Unfortunately I think it can't help with leaked segments, I didn't find > > a way to iterate dshash entries. That's why pg_ts_shared_dictionaries() > > scans pg_ts_dict table instead of scanning dshash table. > > If you're scanning pg_ts_dict, what happens with dictionaries belonging > to other databases? They won't be visible in your local copy of > pg_ts_dict. Between that and the inability to find leaked segments, > I'm not seeing that this has much use-case.
Indeed pg_ts_dict scanning is wrong way here. And pg_ts_shared_dictionaries() is definitely broken. > > Yes unfortunately ALTER TEXT SEARCH DICTIONARY doesn't reload a > > dictionary. TID can help here. I thought about using XID too when I > > started to work on RELOAD command. But I'm not sure that it is a good > > idea, anyway XID isn't needed in current version. > > Actually, existing practice is to check both xmin and tid; see for example > where plpgsql checks if a cached function data structure still matches the > pg_proc row, pl_comp.c around line 175 in HEAD. The other PLs do it > similarly I think. I'm not sure offhand just how much that changes the > risks of a false match compared to testing only one of these fields, but > I'd recommend conforming to the way it's done elsewhere. Thank you for pointing to it! I think it shouldn't be hard to use both xmin and tid. -- Arthur Zakirov Postgres Professional: http://www.postgrespro.com Russian Postgres Company
