PostgreSQL database segsize

On Tue, Jun 30, 2020 at 12:17 AM Bill Glennon <wglennon@gmail.com> wrote:

Hi,

If you are building a Postgresql database from source and you use
option --with-segsize=4, how do you verify that the database segsize is 4GB
and not the default 1GB? Is there a query that you can run?

Or even if you come into a place to support an existing PostgreSQL
database, how do you find out what the database segsize is?

You can run the query "SHOW segment_size" to show the compiled-in value.

--
Magnus Hagander
Me: https://www.hagander.net/ <http://www.hagander.net/&gt;
Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/&gt;

Awesome! That worked. Thank you Magnus!
I should have thought of that earlier. LOL

On Mon, Jun 29, 2020 at 6:33 PM Magnus Hagander <magnus@hagander.net> wrote:

Magnus Hagander <magnus@hagander.net> writes:

On Tue, Jun 30, 2020 at 12:17 AM Bill Glennon <wglennon@gmail.com> wrote:

If you are building a Postgresql database from source and you use
option --with-segsize=4, how do you verify that the database segsize is 4GB
and not the default 1GB? Is there a query that you can run?

You can run the query "SHOW segment_size" to show the compiled-in value.

pg_controldata will show it too, though a bit more opaquely:

Blocks per segment of large relation: 131072

This would be helpful if you have an on-disk database and no running
server.

regards, tom lane