Re: desktop heap usage in windows

Magnus Hagander wrote:
>> fwiw, on my win7 pro 64bit desktop, that reads...
>>
>> %SystemRoot%\system32\csrss.exe ObjectDirectory=\Windows
>> SharedSection=1024,20480,768
>> Windows=On SubSystemType=Windows ServerDll=basesrv,1
>> ServerDll=winsrv:UserServerDllInitialization,3
>> ServerDll=winsrv:ConServerDllInitialization,2 ServerDll=sxssrv,4
>> ProfileControl=Off
>> MaxRequestThreads=16
>>
>> which is larger (768) than the value shown in the KB article [2] (512)
>>
>
> Hmm. I was hoping for orders-of-magniture larger though, that would
> remove the problem completely. This seems to just push it off a little
> bit more (assuming it makes a difference, that should probably be
> tested and not just assumed)
>

I realized I have access to a win7 Pro 32bit system too, the registery
setting is...

%SystemRoot%\system32\csrss.exe ObjectDirectory=\Windows
SharedSection=1024,12288,512 Windows=On SubSystemType=Windows
ServerDll=basesrv,1 ServerDll=winsrv:UserServerDllInitialization,3
ServerDll=winsrv:ConServerDllInitialization,2 ServerDll=sxssrv,4
ProfileControl=Off MaxRequestThreads=16

on XP Pro 32bit, its

%SystemRoot%\system32\csrss.exe ObjectDirectory=\Windows
SharedSection=1024,3072,512 Windows=On SubSystemType=Windows
ServerDll=basesrv,1 ServerDll=winsrv:UserServerDllInitialization,3
ServerDll=winsrv:ConServerDllInitialization,2 ProfileControl=Off
MaxRequestThreads=16

so the first number is 1MB (1024K) on all three systems.

the middle number goes from 3MB on XP32 to 12MB on Win7 32, to 20MB on
Win7 64bit,

the 3rd value goes from 512k, 512k, 768k

now, I do wonder. this IS the user32.dll heap. what library that a
service such as postgres invokes is using objects in the user32 (window
manager) heap?

Microsoft's explanation of these three values is...

The first SharedSection value (1024) is the shared heap size common
to all desktops.
This includes the global handle table, which holds handles to
windows, menus, icons,
cursors, and so forth, and shared system settings. It is unlikely
that you would ever
need to change this value.

The second SharedSection value (3072) is the size of the desktop
heap for each
desktop that is associated with the "interactive" window
station /WinSta0/. User objects
like hooks, menus, strings, and windows consume memory in this
desktop heap.
It is unlikely that you would ever need to change this second
SharedSection value.

The third SharedSection value (512) is the size of the desktop heap
for each
desktop that is associated with a "noninteractive" window station.
If this value
is not present, the size of the desktop heap for noninteractive
window stations
will be same as the size specified for interactive window stations
(the second
SharedSection value).

Every service process executed under a user account will receive a
new desktop
in a noninteractive window station created by the Service Control
Manager (SCM).
Thus, each service executed under a user account will consume the
number of
kilobytes of desktop heap specified in the third SharedSection
value. All services
executed under the LocalSystem account with *Allow Service to
Interact with
the Desktop*/ not/ selected share the desktop heap of the "Default"
desktop in
the noninteractive service windows station (Service-0x0-3e7$).

it goes on to say all 3 of these consume from a 48MB total heap (no idea
if this heap is bigger on 64 bit Windows 7). The 20MB number certainly
implies it must be, since I can create several desktops via remote
desktop connections with fast user switching enabled. that clause
about each service control process using a sepearate heap allocation is
a bit scary in conjunction with that 48MB total limit. this correlates
to the SVCHOST processes, windows runs all the services owned by a given
account in the same SVCHOST process, and uses a seperate SVCHOST for
each unique service account.

did you confirm that in fact its the 3rd number we care about for the
Postgres service? (certainly seems like it to me)