(2011/10/18 2:27), Shigeru Hanada wrote: > The new patch could be applied with some shifts. Regression tests of > core and file_fdw have passed cleanly. Though I've tested only simple > tests, ANALYZE works for foreign tables for file_fdw, and estimation of > costs and selectivity seem appropriate.
Thank you for your testing. > New API AnalyzeForeignTable > =========================== > And I think that AnalyzeForeignTable should be optional, and it would be > very useful if a default handler is provided. Probably a default > handler can use basic FDW APIs to acquire sample rows from the result of > "SELECT * FROM foreign_table" with skipping periodically. It won't be > efficient but I think it's not so unreasonable. I agree with you. However, I think that it is difficult to support such a default handler in a unified way because there exist external data sources for which we cannot execute "SELECT * FROM foreign_table", e.g., web-accessible DBs limiting full access to the contents. > Other issues > ============ > There are some other comments about non-critical issues. > - When there is no analyzable column, vac_update_relstats is not called. > Is this behavior intentional? > - psql can't complete foreign table name after ANALYZE. > - A new parameter has been added to vac_update_relstats in a recent > commit. Perhaps 0 is OK for that parameter. I'll check. > - ANALYZE without relation name ignores foreign tables because > get_rel_oids doesn't list foreign tables. I think that it might be better to ignore foreign tables by default because analyzing such tables may take long depending on FDW. > - IMO logging "analyzing foo.bar" should not be done in > AnalyzeForeignTable handler of each FDW because some FDW might forget to > do it. Maybe it should be pulled up to analyze_rel or somewhere in core. > - It should be mentioned in a document that foreign tables are not > analyzed automatically because they are read-only. OK. I'll revise. > Regards, Best regards, Etsuro Fujita -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers