2011/11/28 Shigeru Hanada <shigeru.han...@gmail.com>: > I agree that allowing users to control which function/operator should be > pushed down is useful, but GUC seems too large as unit of switching > behavior. "Routine Mapping", a mechanism which is defined in SQL/MED > standard, would be the answer for this issue. It can be used to map a > local routine (a procedure or a function) to something on a foreign > server. It is like user mapping, but it has mapping name. Probably it > would have these attributes: > > pg_catalog.pg_routine_mapping > rmname name > rmprocid regproc > rmserverid oid > rmfdwoptions text > > If we have routine mapping, FDW authors can provide default mappings > within extension installation, and users can customize them. Maybe FDWs > will want to push down only functions/operators which have routine > mapping entries, so providing common routine which returns mapping > information of given function/operator, say GetRoutineMapping(procid, > serverid), is useful. > > Unfortunately we don't have it at the moment, I'll fix pgsql_fdw so that > it pushes down only built-in operators, including scalar-array operators.
One difficulty here is that even very simple operators don't necessarily mean the same thing on both sides. In my last job we had a Microsoft SQL database where string equality was case insensitive, and a PostgreSQL database where it wasn't. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers