>Subject: Re: concurrent drop table with fkeys corrupt pg_trigger >Date: Thu, 26 May 2005 09:47:25 +0800" >Qingqing Zhou" <zhouqq ( at ) cs ( dot ) toronto ( dot ) edu> writes >> If we concurrently perform drop/create table (with foreign keys) commands >> several times, we could corrupt the pg_trigger system table. >> > >Anybody reproduced it? > >Regards, >Qingqing
There might be something to this. I'm running in the neighborhood of ~200 writing transactions per second 24/7 on Postgresql 8.1 beta4 at the moment, and getting some related symptoms. There is a table "important_table", whose primary key is an fkey to many, many other tables in the database. This table has no triggers on it. Every morning at roughly 7am, a cronjob kicks off and does a reasonably large number of "CREATE TABLE", "CREATE TRIGGER" (on the new table), and "DROP TABLE" statements (they're part of an inheritance-based table partitioning scheme based on timestamps - it's dropping outdated tables and making new tables for the upcoming timeframes). There are no transactions actually directly using the tables being created or dropped at the time (since they're outside the reasonable range of possible current timestamps). All of the created/dropped tables of course reference the primary key in "important_table". I keep a log of the (very few) failed transactions we get, and every morning at the same time that cron job runs, we get a handful of client transactions failing out during a SELECT statement, with the error: ERROR: too many trigger records found for relation "important_table" But then it all goes back to normal until it happens again the next morning. Remember, "important_table" has no triggers that I know of. I suspect that when tables are in the process of being created or dropped which have fkeys in "important_table", some kind of internal temporary trigger is created on "important_table", and that there's a bug in there somewhere? ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
