On Sun, Oct 26, 2008 at 12:41:39PM -0400, Jonah H. Harris wrote: > On Sat, Oct 25, 2008 at 1:19 PM, Ernesto Quiñones <ernestoq@xxxxxxxxx> wrote: > > I use dbi-link, work fine, but I have problems when I call mysql > > tables "linked" and these tables are big, maybe a millon records, > > the answers is really slow, I need to wait 5 or more minutes to > > have an answer in a single query like this "select * from table > > limit 10", I am thinking maybe dbi-link download all the data to > > pgsql before to give me the answer. > > Yes, that's what Postgres is doing. DBI-link is currently incapable > of pushing down the predicate to the remote system because Postgres > can't give it access to the predicate. More precisely, Postgres is (as yet) incapable of giving DBI-Link the information it needs. > > Anybody knows how improve this? > > If I have to push the predicate down, I'll generally write a > set-returning function which takes some of the predicate, limit, and > offset info to build a dynamic sql query against the remote database > using dblink. That's one way. For others, I can help out on a consulting basis :) Cheers, David. -- David Fetter <david@xxxxxxxxxx> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@xxxxxxxxx Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
