Re: Table lock while adding a column and clients are logged in - Mailing list pgsql-general

From Sven Haag
Subject Re: Table lock while adding a column and clients are logged in
Date
Msg-id 20110402101339.125180@gmx.net
Whole thread Raw
In response to Re: Table lock while adding a column and clients are logged in  (Guillaume Lelarge <guillaume@lelarge.info>)
Responses Re: Table lock while adding a column and clients are logged in
List pgsql-general
yes i saw that in the documentation too. i guess it doesn't matter what kind of lock level the odbc driver is using
(row-lock)?

but how can it be, that in oracle and sqlserver this is not happening?



-------- Original-Nachricht --------
> Datum: Sat, 02 Apr 2011 11:38:29 +0200
> Von: Guillaume Lelarge <guillaume@lelarge.info>
> An: Sven Haag <sven-haag@gmx.de>
> CC: pgsql-general@postgresql.org
> Betreff: Re: [GENERAL] 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

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