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Home > Archive > SQL Anywhere database > October 2005 > Property: MaxCacheSize is same as initial cache size
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Property: MaxCacheSize is same as initial cache size
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| Peter Simonsen 2005-10-27, 7:40 am |
| ASA 9.0.2.3044 & ASA 7.0.4.3538
Win XP/2K
1GB ram
On both ASA7 and ASA9 the only parameter supplied to dbeng/dbsrv is the
initial cache size (-c 256M). Still it look like ASA doesn't try to
allocate more cache when needed, as the maxcachesize defaults to the
initial cache size.
This is from the server log (ASA7 & ASA9 shows the same):
262144K of memory used for caching
Minimum cache size: 262144K, maximum cache size: 262144K
Using a maximum page size of 4096 bytes
Am I missing something?
It looks like dynamic cache sizing is disabled, as both min and max
cache size defaults to initial cache size?!
regards/Peter Simonsen
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| Nick Elson 2005-10-27, 7:40 am |
| If you look at the documented default for -ch you will note
that
By default the upper limit is approximately the lower of
256 Mb and 90% of the physical memory of the machine.
so by setting -c to the max. default you are specifying this
to be the expected behaviour.
"Peter Simonsen" <"Peter Simonsen"> wrote in message
news:43563190$1@foru
ms-1-dub...
> ASA 9.0.2.3044 & ASA 7.0.4.3538
> Win XP/2K
> 1GB ram
>
> On both ASA7 and ASA9 the only parameter supplied to dbeng/dbsrv is the
> initial cache size (-c 256M). Still it look like ASA doesn't try to
> allocate more cache when needed, as the maxcachesize defaults to the
> initial cache size.
>
> This is from the server log (ASA7 & ASA9 shows the same):
>
> 262144K of memory used for caching
> Minimum cache size: 262144K, maximum cache size: 262144K
> Using a maximum page size of 4096 bytes
>
> Am I missing something?
>
> It looks like dynamic cache sizing is disabled, as both min and max
> cache size defaults to initial cache size?!
>
> regards/Peter Simonsen
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| John Smirnios 2005-10-27, 7:40 am |
| We also recognized that the 256MB limit was too low for most modern
configurations (at the time the default was made, 256MB was a _lot_ of
memory). Changing defaults in EBFs is a sensitive thing so we have
changed it for Jasper as described below.
The default maximum cache size on NT is now limited to the lesser of the
following:
1) 90% * (total_physical_memo
ry - 4MB), but no less than 2MB
2) available address space - 512MB
Previously, the #2 above was hard-wired as 256MB. Available address
space is (very roughly) 1.7GB on 32-bit XP & Server, 2.7GB on 32-bit
Advanced, Enterprise & Datacenter Servers (if /3GB is in the boot.ini),
3.7 GB for 32-bit executables running on Windows x64 Edition, and
effectively infinite (9TB or so) on 64-bit versions.
These changes affect conventional caches only -- not AWE cache.
-john.
--
John Smirnios
Senior Software Developer
iAnywhere Solutions Engineering
Whitepapers, TechDocs, bug fixes are all available through the iAnywhere
Developer Community at http://www.ianywhere.com/developer
Nick Elson wrote:
> If you look at the documented default for -ch you will note
> that
>
> By default the upper limit is approximately the lower of
> 256 Mb and 90% of the physical memory of the machine.
>
> so by setting -c to the max. default you are specifying this
> to be the expected behaviour.
>
>
> "Peter Simonsen" <"Peter Simonsen"> wrote in message
> news:43563190$1@foru
ms-1-dub...
>
>
>
>
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| Peter Simonsen 2005-10-27, 7:40 am |
| John Smirnios wrote:
> We also recognized that the 256MB limit was too low for most modern
:
> These changes affect conventional caches only -- not AWE cache.
> -john.
Thanks for the info, Nick and John.
Regards/Peter Simonsen
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| Peter,
To override the 256M default, simply add -ch 1500m or whatever you want
the actual max to be to your startup parameters.
Peter Simonsen wrote:
> ASA 9.0.2.3044 & ASA 7.0.4.3538
> Win XP/2K
> 1GB ram
>
> On both ASA7 and ASA9 the only parameter supplied to dbeng/dbsrv is the
> initial cache size (-c 256M). Still it look like ASA doesn't try to
> allocate more cache when needed, as the maxcachesize defaults to the
> initial cache size.
>
> This is from the server log (ASA7 & ASA9 shows the same):
>
> 262144K of memory used for caching
> Minimum cache size: 262144K, maximum cache size: 262144K
> Using a maximum page size of 4096 bytes
>
> Am I missing something?
>
> It looks like dynamic cache sizing is disabled, as both min and max
> cache size defaults to initial cache size?!
>
> regards/Peter Simonsen
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