On Fri, Nov 1, 2019 at 11:15 AM Konstantin Knizhnik <k.knizh...@postgrespro.ru> wrote: > It seems to me that I have found quite elegant solution for per-backend > statistic for GTT: I just inserting it in backend's catalog cache, but not in > pg_statistic table itself. > To do it I have to add InsertSysCache/InsertCatCache functions which insert > pinned entry in the correspondent cache. > I wonder if there are some pitfalls of such approach?
That sounds pretty hackish. You'd have to be very careful, for example, that if the tables were dropped or re-analyzed, all of the old entries got removed -- and then it would still fail if any code tried to access the statistics directly from the table, rather than via the caches. My assumption is that the statistics ought to be stored in some backend-private data structure designed for that purpose, and that the code that needs the data should be taught to look for it there when the table is a GTT. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
