Обсуждение: Per-session memory footprint (9.0/windows)

Folks,


I run a PG (currently 8.4, but will shortly migrate to 9.0) database on
Windows Server 2003 that supports a desktop application which opens a
few long-running sessions per user. This is due to the Hibernate
persistence layer and the "one session per view" pattern that is
recommended for such applications.
These sessions usually load a pile of data once to display to the user,
and then occasionally query updates of this data or even fetch single
rows over a long time (like a few hours).

It seems that each of the server postmaster.exe processes takes up
approx. 5 MB of server memory (the "virtual memory size" column in task
manager), and I guess this truly is the private memory these processes
require. This number is roughly the same for 8.4 and 9.0 .


As there are many, many such server processes running, is there anything
I can do to reduce/optimize the per-session memory footprint?

I'm aware of the sort_mem etc. parameters
(http://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server ) but
these seem to only apply to the execution of queries, not to sessions
that mainly "sit around waiting", right?


Thank you for any hints!

    -hannes

Scott,


>     It seems that each of the server postmaster.exe processes takes up
>     approx. 5 MB of server memory (the "virtual memory size" column in task
>     manager), and I guess this truly is the private memory these processes
>     require. This number is roughly the same for 8.4 and 9.0 .
>
> Task manager is mis-leading as multiple processes are sharing memory.
> You need process explorer

That's exactly why I did not use the "default" columns of the Task
Manager, but "virtual memory size". I now compared the numbers to the
"private memory" column of Process Explorer, and Process Explorer shows
about 800k even more usage the the Task Manager.

It is still about 5 MB of private memory per "idle" backend process. Is
there anything I can do to optimize?


Thanks again,

    -hannes

Hannes Erven <hannes@erven.at> writes:
> It is still about 5 MB of private memory per "idle" backend process. Is
> there anything I can do to optimize?

That sounds about the right ballpark for a working backend process with
caches loaded up.  If that's too much for you, you ought to be using
connection pooling.

            regards, tom lane