On Mon, Jul 27, 2009 at 7:51 PM, Tom Lane<t...@sss.pgh.pa.us> wrote: > (In fact, in a real sense these ARE join problems ... maybe we should > stop thinking of them as fire-a-bunch-of-triggers and instead think of > executing a single check query with appropriate WHERE clause ...)
A while back I suggested keeping the deferred trigger list in tuplestore format and executing the trigger check as a query between the materialized tuplestore of and the tuples on disk. I love the idea of doing a full SQL query but the problem is that there's no particular reason to assume that a deferred trigger list large enough to warrant a wholesale check is actually a significant percentage of the table. It might only take a few hundred or few thousand checks to warrant a bitmap index scan instead of repeated index probes but a plain SQL query with no reference back to the deferred list would have to check all the millions of rows in the table for no purpose. For foreign keys I was picturing some way to issue an SQL statement like "SELECT from tabletocheck where ctid in (<magic parameter>) and not exists (select 1 from referenced_table where pk = tabletocheck.fk)" and then somehow pass the list of ctids from the deferred list. -- greg http://mit.edu/~gsstark/resume.pdf -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
