Re: Table lock while adding a column and clients are logged in

Le 02/04/2011 11:09, Sven Haag a écrit :
> hello pg fans,
>
> we have an application that communicates via ODBC directly to the postgres database.
>
> if i'm trying to add an additional column to a table in pgadmin while clients are logged in, pgadmin hangs. only if all cients are logged out it returns to the normal state. according to our consultant of the application this behavior doesn't appear in oracle or sql-server.
>
> how can i avoid this?
>

When you add a new column to a table, the session needs an
AccessExclusiveLock to this table, which means no one can have a lock on
the object while you add the column. IOW, pgAdmin (and any other tool)
will hang until no one works on the table. If it's a heavily used table,
there's not much you can do about it, but wait.

--
Guillaume
http://www.postgresql.fr
http://dalibo.com