Re: Number of connections still limited on Windows 64-bit? - Mailing list pgsql-admin

Hello Andreas,

Am 15.12.2011 18:40, schrieb [email protected]:
> Zitat von [email protected]:

>> -------- Original-Nachricht --------
>>> Datum: Thu, 08 Dec 2011 13:04:30 +0100
>>> Von: [email protected]
>>> Zitat von Jan-Peter Seifert <[email protected]>:
>>
>>> > I wonder whether the number of connections is still limited on
>>> > Windows 64-bit if you also use a 64-bit version of PostgreSQL:
>>
>>>
http://wiki.postgresql.org/wiki/Running_%26_Installing_PostgreSQL_On_Native_Windows#I_cannot_run_with_more_than_about_125_connections_at_once.2C_despite_having_capable_hardware
>>>
>>
>>> http://support.microsoft.com/kb/947246/en-us
>>
>> So the default setting for Windows 7 64-Bit seems to be:
>> SharedSection=1024,20480,768
>>
>> Makes me wonder whether PostgreSQL ( as a service ) still uses the
>> 'Non-interactive desktop heap' for connections then.
>
> As far as i understand not PostgreSQL is using the heap but the system
> component user32.dll does. Not sure why user32.dll is needed but i
> remember Oracle at least back in 9.x days had the very same problem.
>
>> I used pgbench for testing 500 connections ( max_connections set to
>> 600 ):
>> Initialize:
>> pgbench -i -U postgres -h host -p port
>> Test:
>> pgbench -U postgres -h host -p port -c 500
>> Verify:
>> SELECT COUNT(*) FROM pg_stat_activity;
>>
>> The non-interactive Desktop Heap has been increased by just a half -
>> yet the number of connections can obviously be much higher than 200. I
>> guess the connections don't need less memory now though.
>
> I think i have read somewhere that MS has optimized the Desktop Heap
> usage in Vista and later, but not sure where it was.

I guess you mean this blog post:

http://blogs.msdn.com/b/ntdebugging/archive/2008/03/20/the-default-interactive-desktop-heap-size-has-been-increased-on-32-bit-vista-sp1.aspx

This seems to be an interesting post, too:
http://thundaxsoftware.blogspot.com/2011/10/monitoring-desktop-heap-memory-and_17.html

>> Do the services share the same desktop (heap) or does each
>> (PostgreSQL) service has its own ( if I register each service for a
>> different Windows user?).
>
> To be honest i don't know at all...

I'll have a look then.

Thank you very much for your comments,

Peter