From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dennis Wang <dennis_02_2002@hotmail.com>
Cc: Postgresql Help <pgsql-interfaces@postgresql.org>
Subject: Re: URGENET: ALTER statement exectuation hangs when it is executed multiple time on a table
Date: Thu, 10 Jan 2008 20:09:58 -0500
Message-ID: <20042.1200013798@sss.pgh.pa.us> (raw)
In-Reply-To: <BAY137-W832842CAB356C78B3C728D64B0@phx.gbl>
References: <BAY137-W832842CAB356C78B3C728D64B0@phx.gbl>
Dennis Wang <dennis_02_2002@hotmail.com> writes:
> The actual PostgreSQL commands are:
> ALTER TABLE warngrid ALTER COLUMN id SET DEFAULT (nextval('warngrid_seq')* 10)+1;
> COPY warngrid FROM 'warngrid.csv' CSV HEADER;
> ALTER TABLE warngrid ALTER COLUMN id DROP DEFAULT;
> For the first time, these operation execute fine. Then I do these steps:
> 4. delete all the records in the table
> 5. rerun the shell script to copy records.
> Then, the ALTER statement in step 1 hanging there.
Did you do all this in one database session, or more than one? If the
latter, maybe you haven't committed the transaction that did the DELETE?
> I did check the lock state of the warngrid table, it says the process created by the ALTER statement hold an "AccessExclusiveLock" on the table.
Did it actually *have* that lock, or was it waiting for it (granted = f
in pg_locks)?
regards, tom lane
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To: pgsql-interfaces@postgresql.org
Cc: tgl@sss.pgh.pa.us, dennis_02_2002@hotmail.com
Subject: Re: URGENET: ALTER statement exectuation hangs when it is executed multiple time on a table
In-Reply-To: <20042.1200013798@sss.pgh.pa.us>
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