On 03/03/2011 11:36 PM, Noah Misch wrote: > Does relation 16902 (attribute_summary) have a foreign key constraint over the > sequence_number column, in either direction, with relation 16896? That would > explain it: > > session 1: ALTER TABLE attribute_summary ... <sleeps after relation_openrv in > transformAlterTableStmt> > session 2: SELECT 1 FROM rel16896 LIMIT 0; > session 2: SELECT 1 FROM attribute_summary LIMIT 0; <blocks> > session 1: <wakes up; continues ALTER TABLE: deadlock upon locking rel16896>
Ah, OK -- then that would explain it as there are foreign keys on that column. Thanks, hadn't thought about that aspect. > Granted, the cure may be worse than the disease. Right. I've already advised they shut down the application during the alter table, which they can do (and in fact already do -- they were restarting the application just prior to this step, which really makes no sense anyway). Thanks, Joe -- Joe Conway credativ LLC: http://www.credativ.us Linux, PostgreSQL, and general Open Source Training, Service, Consulting, & 24x7 Support
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