On Mon, Jun 8, 2015 at 10:29 AM, Jason Dusek <jason.dusek@xxxxxxxxx> wrote: > The databases involved are all Postgres 9.4 or 9.3. The FDW is the Postgres > FDW. > > The join node (the one from which queries are issued) is Postgres 9.4 > installed yesterday from the Postgres Apt repository. It's using the version > of the wrapper that is shipped with that package. > > The databases being queried -- the ones with the actual tables -- are both > Postgres 9.3.5, on Amazon RDS. > Sorry, I forgot to include pgsql-general on the address list for my reply. It seems that postgres_fdw in Postgres 9.3 and 9.4 supports where clause push-down according to the documentation: http://www.postgresql.org/docs/9.3/static/postgres-fdw.html "postgres_fdw attempts to optimize remote queries to reduce the amount of data transferred from foreign servers. This is done by sending query WHERE clauses to the remote server for execution, and by not retrieving table columns that are not needed for the current query. To reduce the risk of misexecution of queries, WHERE clauses are not sent to the remote server unless they use only built-in data types, operators, and functions. Operators and functions in the clauses must be IMMUTABLE as well." I'm guessing that postgres_fdw sees that one of your function calls is IMMUTABLE, so it thinks it is unsafe to push-down. It is probably your call to NOW(). You might want to try replacing that with a literal somehow, if you can. Geoff -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
