Huge number of pg_temp and pg_toast_temp schemas

"Andrus" <kobruleht2@hot.ee> writes:

Hi!
Postgres 12 database contains huge number of pg_temp and pg_toast_temp schemas named
pg_temp_1 .. pg_temp_126
and
pg_toast_temp_1 .. pg_toast_temp_126

This is an unsurprising state, if you routinely have a hundred-plus
connections that sometimes create temp tables. Each such session
needs schemas to keep its temp tables in. The temp tables are
deleted at session exit, but we don't bother to remove the schema
entries, figuring that they'll probably be needed again later, and
a couple of rows in pg_namespace is negligible overhead anyway.

How to delete them automatically and prevent appear in future?

You can't (well, if you're a superuser you could drop those schemas,
but you can't prevent them from being recreated when needed). And it's
really not worth trying. If you do try you're pretty likely to break
concurrent usage of temp tables.

Cluster stopped since disk decomes full and streaming async replication is used. Maybe one of those or some other factor created or
continues to create those schemas. Postgres 12.2 in Debian 10 is used.

It's entirely possible that some temp table took up too much disk
space, but ~250 rows in pg_namespace is not the cause of that problem.

regards, tom lane

Hi!

Thank you.

This is an unsurprising state, if you routinely have a hundred-plus
connections that sometimes create temp tables. Each such session
needs schemas to keep its temp tables in. The temp tables are
deleted at session exit, but we don't bother to remove the schema
entries, figuring that they'll probably be needed again later, and
a couple of rows in pg_namespace is negligible overhead anyway.

How to hide temp schemas from pgAdmin 4 tree?
For such large number of temporary schemas pgAdmin schema tree view becomes polluted and makes database management difficult.
I turned most of Nodes options in PgAdmin options off but pgadmin still shows them. It shows also pg_toast schema.

Andrus.

On 4/10/20 11:06 AM, Andrus wrote:

Hi!

Thank you.

This is an unsurprising state, if you routinely have a hundred-plus
connections that sometimes create temp tables.� Each such session
needs schemas to keep its temp tables in.� The temp tables are
deleted at session exit, but we don't bother to remove the schema
entries, figuring that they'll probably be needed again later, and
a couple of rows in pg_namespace is negligible overhead anyway.

How to hide temp schemas from pgAdmin 4 tree?
For such large number of temporary schemas� pgAdmin schema tree view
becomes polluted and makes database management difficult.
I turned most of Nodes options in PgAdmin options off but pgadmin still
shows them. It shows also pg_toast schema.

That's something you probably need to ask the pgAdmin folks:

https://www.postgresql.org/list/pgadmin-support/

Andrus.

--
Adrian Klaver
adrian.klaver@aklaver.com