Re: how much memory (work_mem) is a query using?

On Tue, Jun 30, 2009 at 5:20 AM, Kevin Kempter
<kevink(at)consistentstate(dot)com>wrote:

> Hi all;
>
> is it possible to see how much work_mem memory a particular session is
> using?
>
>
>
>
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Hi,

You can’t able to see memory allocated for the particular session in
database.

The work_mem specifies the amount of memory to be used by internal sort
operations and hash tables before switching to temporary disk files. The
default value in database is 1MB.

Several running sessions could be doing such operations concurrently, so the
total memory used could be many times the value of work_mem (It is necessary
to keep this fact in mind when choosing the value).

Sort operations are used for ORDER BY, DISTINCT, and merge joins. Hash
tables are used in hash joins, hash-based aggregation, and hash-based
processing of IN subqueries.
Thanks & Regards,
Raghu Ram