Postgres locks table schema?

Started by Stas Oskinover 20 years ago4 messagesgeneral
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#1Stas Oskin
stas@neo.co.il

Hi.

When running SQL scripts, which change the tables' schema, we sometimes
experience a lock of these tables' schema. The lock occurs on the first
command of the script, on the first modified table. When this occurs, no
further schema modification for this table is possible, until the server is
restarted, which is very problematic for a production environment.

Perhaps someone is familiar with this behavior, and how it can be resolved,
without the restart of the server?

The server used is PostgreSQL 8.0.3, and the OS is Fedora Core 3.

Thanks.

Stas Oskin.

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Stas Oskin (#1)
Re: Postgres locks table schema?

"Stas Oskin" <stas@neo.co.il> writes:

When running SQL scripts, which change the tables' schema, we sometimes
experience a lock of these tables' schema. The lock occurs on the first
command of the script, on the first modified table. When this occurs, no
further schema modification for this table is possible, until the server is
restarted, which is very problematic for a production environment.

Try committing the transaction that performed the schema modification
;-)

regards, tom lane

#3Scott Marlowe
smarlowe@g2switchworks.com
In reply to: Stas Oskin (#1)
Re: Postgres locks table schema?

On Wed, 2005-09-21 at 12:51, Stas Oskin wrote:

Hi.

When running SQL scripts, which change the tables' schema, we
sometimes experience a lock of these tables' schema. The lock occurs
on the first command of the script, on the first modified table. When
this occurs, no further schema modification for this table is
possible, until the server is restarted, which is very problematic for
a production environment.

Perhaps someone is familiar with this behavior, and how it can be
resolved, without the restart of the server?

The server used is PostgreSQL 8.0.3, and the OS is Fedora Core 3.

Have you got a test case that reproduces this in some way? I'm guessing
Tom's got it right on committing the transaction, but without knowing
EXACTLY what you're doing, we're just guessing here.

#4Stas Oskin
stas@neo.co.il
In reply to: Tom Lane (#2)
Re: Postgres locks table schema?

Hi.

I will give it a try. Although, I do remember that the lock occurs on the
first transaction - so basically there should be nothing to commit yet?

Thanks,
Stas.

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
Sent: Wednesday, September 21, 2005 9:35 PM
To: Stas Oskin
Cc: pgsql-general@postgresql.org
Subject: Re: [GENERAL] Postgres locks table schema?

"Stas Oskin" <stas@neo.co.il> writes:

When running SQL scripts, which change the tables' schema, we sometimes
experience a lock of these tables' schema. The lock occurs on the first
command of the script, on the first modified table. When this occurs, no
further schema modification for this table is possible, until the server

is

restarted, which is very problematic for a production environment.

Try committing the transaction that performed the schema modification
;-)

regards, tom lane