Re: PostgreSQL backend process high memory usage issue

On Fri, Apr 8, 2011 at 5:07 PM, Shianmiin <Shianmiin(at)gmail(dot)com> wrote:
>
> Merlin Moncure-2 wrote:
>>
>> On Fri, Apr 8, 2011 at 2:00 PM, Shianmiin &lt;Shianmiin(at)gmail(dot)com&gt;
>> wrote:
>>> Further clarification,
>>>
>>> if I run two concurrent threads
>>>
>>> pgbench memoryusagetest -c 2 -j 2 -T180 -f test.sql
>>>
>>> both backend processes uses 1.5GB and result in 3GB in total.
>>
>> yes. could you please post a capture of top after running the modified
>> test that does not run in single transaction.
>>
>> merlin
>>
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>
> Here you are.
>
> http://postgresql.1045698.n5.nabble.com/file/n4292010/PostgreSQLBackendMemoryUsage.gif
> PostgreSQLBackendMemoryUsage.gif
>
> The screen shot was taken with running the following command
>
> pgbench memoryusagetest -c 2 -j 2 -T1800 -f test.sql
>
> I have to set the test time longer so that I got the chance to take the
> snapshot because if pgbench finishes, the connection will be gone.
>
> The snapshot was taken when I wait until the memory usage stable at 1.5GB.
>
> Please note in this tests, there are two PostgreSQL backend processes, each
> use 1.5GB of memory.

I am not seeing your results. I was able to run your test on a stock
config (cut down to 50 schemas though) on a vm with 512mb of memory.
What is your shared buffers set to?

merlin