Guy Rouillier wrote: > Back in March 2005, I started an email thread titled "Debugging > deadlocks". Most of the experienced PGers participated in that thread. > The basic issue at that time was that inserting a row into a table with a > foreign key placed an exclusive row-level lock (SELECT FOR UPDATE) on the > reference table (the table to which the foreign key refers). If you > happen to do inserts on two different tables, each with a foreign key to > the same reference table, deadlocks are pretty easy to create. This is > especially true if the reference table has low cardinality, which is > often the case. > > I don't know if this situation has been improved since that time.
We fixed this in 8.1 IIRC. FKs now use "SELECT FOR SHARE", which only takes a shared lock not exclusive, and does away with most deadlocks of this ilk. Of course, there are other ways to get in deadlock still. -- Alvaro Herrera http://www.amazon.com/gp/registry/DXLWNGRJD34J "I can see support will not be a problem. 10 out of 10." (Simon Wittber) (http://archives.postgresql.org/pgsql-general/2004-12/msg00159.php) -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
