Mohammad,
> I'm doing a research in distributing DB & application.
>
> I want to measure the size of the intermediate relation (I'm using
> Linux
> SuSe 7.1 "default installations" in 9 workstations each has a table),
> when I perform a SELECT operation (it gives me intermediate relation,
> I
> have to send this relation into next workstation to perform the next
> operation) how can I measure the size of this relation.?
>
> Each workstation has 256 Mb RAM, consider the intermediate relation
> dos
> not fit in the RAM, then it will goes to SWAP area, then in which
> form
> and size?
Check TechDocs: http://techdocs.postgresql.org
There are three articles about PostgreSQL database optimization there,
all of which contain useful material related to your question.
You will also want to examine the Administrator's Guide in the online
documentation:
http://www.postgresql.org/idocs/index.php?admin.html
And this section of the developer's guide:
http://www.postgresql.org/idocs/index.php?page.html
All in all, your question does not have a simple answer because
PostgreSQL is configurable, both at compile time and at run time, in
ways that profoundly affect Postgres' disk, memory, and file usage.
-Josh Berkus