Hi,
since we use PSQLV8 the following has been changed: the timestamp of
btrieve-files in the filesystem does not change until the btrieve file
is closed. All data are written correctly to the file, but the file
itself is not "touched".
In former version of PSQL this was different: filesystem timestaps where
updated immediately.
Is this a known issue or does this point to a errornous instalation?

Any hint will be wellcome.

Mircea

p.s.: Cache allcoation size is set to 512 MB, Main-memory of the server
is 1 GB. Create file Version is set to 7.x.
The server-system is Win2000 Server, NTFS.

The timestamp of the file is updated by the operating system itself
not the database engine.

It has been observed that when the "System Cache" setting is "on" the
OS does update the timestamps in an ongoing basis. The default value
for the System Cache setting has changed to off with V8 due to the
dynamic caching inside the database engine. The OS would use the
memory for generic file IO caching instead of the dynamic specialized
database cache built into the engine.

Setting the Cache Allocation to 1/2 the available memory will not let
the dynamic cache work at the highest efficiency. Of course if you
entire data set fits in cache allocation I would not change it as the
dynamic cache is not as efficient as the normal cache.

Leonard

On Tue, 29 Jun 2004 09:44:18 +0200, nmm
<Mircea.Malarski (AT) onlinehome (DOT) de> wrote:

Leonard wrote:
Thank you for your response.


1 GB on the harddrive.

of dynamic cache at all? Or, if this is to strong, way not reset the
default value for the System Cache setting to "on"?

Regards
Mircea

On Sun, 04 Jul 2004 20:42:38 +0200, nmm
<Mircea.Malarski (AT) onlinehome (DOT) de> wrote:

If you really want to take advantage of the dynamic cache regular
cache would need to be lowered so that the dynamic cache has some
memory to work with.
Since the dynamic cache is read-only clean pages, optimized for
database access and it can (usually without issue although not always)
use 90% of the memory it may be possible for it to cache all the data
in the data files. Don't forget that there is some empty space in the
data files and the applicaiton rarely will use all the indexes in a
data file meaning that it probably could cache 1GB of data files in
about 800MB.
The dynamic cache is optimized for database access. The OS cache is
generic and often times caches the same information as is already in
the regular cache.
It turns out the dynamic cache is better to use than the OS cache in
most cases as it does not double cache the information and is
optimized for the database engine.

In most cases the crosover point to use OS cache instead of dynamic
cache come when there is 4GB or more of RAM in the server. The OS
will not allow the database process to use more than 2GB so at that
point the OS cache while not as efficient as the dynamic cache can
just take advantage of so much more memory in the machine that it
would work better anyway.

Leonard