Обсуждение: Reindexing primary keys without locking

Glyn Astill <glynastill@yahoo.co.uk> wrote:

> Does anyone know of any tricks to replace primary key indexes
> without using reindex? Or any other method that will not lock the
> table for an extended amount of time on 8.4?
>
> I've got a bloated primary key index on a table and I'd like to
> try and clean it up without downtime.

You could create a unique index concurrently on the same columns.
Perhaps that would help with performance problems from the bloat
until you had a window to drop the redundant index and reindex the
table?

-Kevin

On Wed, Jun 1, 2011 at 7:38 PM, Glyn Astill <glynastill@yahoo.co.uk> wrote:
> Hi Guys,
> Does anyone know of any tricks to replace primary key indexes without using
> reindex? Or any other method that will not lock the table for an extended
> amount of time on 8.4?
> I've got a bloated primary key index on a table and I'd like to try and
> clean it up without downtime.

If you are brave, http://pqxx.org/development/libpqxx/wiki/PrimaryKeyTransplant

If you go this route, ensure you have a test environment and ensure
you can dump and restore your db schema after applying the patch, and
that the diff of the before and after schemas checks out. If you screw
up, you can end up with crazy things like multiple indexes with the
same name and other stuff making your database unrecoverable.

--
Stuart Bishop <stuart@stuartbishop.net>
http://www.stuartbishop.net/

On Mon, Jun 13, 2011 at 6:47 AM, Stuart Bishop <stuart@stuartbishop.net> wrote:
> On Wed, Jun 1, 2011 at 7:38 PM, Glyn Astill <glynastill@yahoo.co.uk> wrote:
>> Hi Guys,
>> Does anyone know of any tricks to replace primary key indexes without using
>> reindex? Or any other method that will not lock the table for an extended
>> amount of time on 8.4?
>> I've got a bloated primary key index on a table and I'd like to try and
>> clean it up without downtime.
>
> If you are brave, http://pqxx.org/development/libpqxx/wiki/PrimaryKeyTransplant
>
> If you go this route, ensure you have a test environment and ensure
> you can dump and restore your db schema after applying the patch, and
> that the diff of the before and after schemas checks out. If you screw
> up, you can end up with crazy things like multiple indexes with the
> same name and other stuff making your database unrecoverable.

Stuart,

That looks interesting. There's a similar process in the PostgreSQL
Admin Cookbook, though our work was independent.

I guess that's because in 9.0 and below it really is the only way to
make it work correctly.

Will look for your work in future, thanks.

--
 Simon Riggs                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services