On Tue, 2021-03-30 at 12:36 +0530, Devendra Yadav wrote: > Hope everything is well with you. Thanks, yes. I hope you are fine too. > We are running on PostgreSQL v 12.1 , Redhat 7.8. > We are running a query - ALTER TABLE mytable ADD COLUMN deposited DOUBLE PRECISION; > > This query is blocked by pid 0. It's not a postgres PID and won't allow to terminate from postgres. > What would be the way forward to troubleshoot this? That is probably a stale prepared transaction. Look into "pg_prepared_xacts" for any prepared transactions and use ROLLBACK PREPARED 'name'; to remove stale entries. When using prepared transactions, you must use a transaction manager that does these things for you. Also, you should monitor prepared transactions. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com
