Re: adding foreign key constraint locks up table - Mailing list pgsql-performance

From Florian Weimer
Subject Re: adding foreign key constraint locks up table
Date
Msg-id 8239p8rd2f.fsf@mid.bfk.de
Whole thread Raw
In response to Re: adding foreign key constraint locks up table  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: adding foreign key constraint locks up table
List pgsql-performance
* Tom Lane:

>> Do you mean that the ALTER query and subsequent queries are shown as
>> "waiting" in pg_stat_activity?  In this case, I'm also wondering why
>> this is inecessary.
>
> ALTER ADD FOREIGN KEY must lock both tables to add triggers to them.

But why is such a broad lock needed?  If the table was created in the
current transaction and is empty, the contents of the foreign key
table should not matter.

--
Florian Weimer                <fweimer@bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
Kriegsstraße 100              tel: +49-721-96201-1
D-76133 Karlsruhe             fax: +49-721-96201-99

pgsql-performance by date:

Previous
From: Greg Smith
Date:
Subject: Re: Performance of PostgreSQL over NFS
Next
From: Greg Smith
Date:
Subject: Re: concurrent IO in postgres?