Hi,

We have a client who has had issues for quite some time.  They recently
upgraded switches and moved to a dedicated server but are still experiencing
immense problems.  We have a number of other clients of similar size in user
terms and input wise without any apparent issues.

As I am struggling a bit to find a solution, was wondering if someone could
help decipher what the following log items mean and how they would occur:

9/24/2008 12:41:57 PM Session not found, re-connection rejected [Address:
192.168.11.121 Version: 3.30 Request: REQUEST_RECONNECT Thread: 5768
Session: 0]

That happened for a good two minutes but after a DBISAM server shutdown and
restart.  I presume maybe the application was still open and making requests
after restart?

9/24/2008 12:34:43 PM Engine error - Access violation at address 004B998A in
module 'dbsrvr.exe'. Read of address 000018EC [Address: 192.168.11.28
Version: 3.30 Request: REQUEST_MODIFYRECORD Thread: 5480 Session: 0]
9/24/2008 12:34:43 PM Engine error - Access violation at address 004B998A in
module 'dbsrvr.exe'. Read of address 000018EC [Address: 192.168.11.28
Version: 3.30 Request: REQUEST_MODIFYRECORD Thread: 5240 Session: 0]

Accecc violations in the serve engine always concerns me.

9/24/2008 12:32:20 PM Engine error - DBISAM Engine Error # 10249 General
lock failure with the table 'BOOKING' [Address: 192.168.11.40 Version: 3.30
Request: REQUEST_MODIFYRECORD Thread: 5956 Session: 555939432]

There were alot of these lock failures over a 10 minute period or so.

9/24/2008 11:55:51 AM Connection closed [Address: 192.168.11.21 Version:
3.30 Thread: 3360 Session: 248619036]
9/24/2008 11:55:51 AM Connection closed [Address: 192.168.11.21 Version:
3.30 Thread: 4932 Session: 248687964]
9

This close occurred but there were no apparent logout bu user.  Should this
normally happen?

As you can see it is V3.30.

Thanks

Alex

Alex,

<< We have a client who has had issues for quite some time.  They recently
upgraded switches and moved to a dedicated server but are still experiencing
immense problems.  We have a number of other clients of similar size in user
terms and input wise without any apparent issues. >>

What exactly is the problem that they're experiencing ?  You haven't
actually stated what the problem is.

<< As I am struggling a bit to find a solution, was wondering if someone
could help decipher what the following log items mean and how they would
occur:

9/24/2008 12:41:57 PM Session not found, re-connection rejected [Address:
192.168.11.121 Version: 3.30 Request: REQUEST_RECONNECT Thread: 5768
Session: 0]

That happened for a good two minutes but after a DBISAM server shutdown and
restart.  I presume maybe the application was still open and making requests
after restart? >>

Yes, it means that the application is still up and trying to execute calls
to the server using a session ID that no longer exists in the DBISAM
Database Server.  Why are they shutting down the server with applications
still connected ?

<< 9/24/2008 12:34:43 PM Engine error - Access violation at address 004B998A
in module 'dbsrvr.exe'. Read of address 000018EC [Address: 192.168.11.28
Version: 3.30 Request: REQUEST_MODIFYRECORD Thread: 5480 Session: 0]
9/24/2008 12:34:43 PM Engine error - Access violation at address 004B998A in
module 'dbsrvr.exe'. Read of address 000018EC [Address: 192.168.11.28
Version: 3.30 Request: REQUEST_MODIFYRECORD Thread: 5240 Session: 0]

Accecc violations in the serve engine always concerns me. >>

Did you run a repair on the tables to ensure that there isn't any corruption
?

<< 9/24/2008 12:32:20 PM Engine error - DBISAM Engine Error # 10249 General
lock failure with the table 'BOOKING' [Address: 192.168.11.40 Version: 3.30
Request: REQUEST_MODIFYRECORD Thread: 5956 Session: 555939432]

There were alot of these lock failures over a 10 minute period or so. >>

Is your application using transactions at all ?

<< This close occurred but there were no apparent logout bu user.  Should
this normally happen? >>

Sure, a session can be disconnected but not logged out.  That's how we allow
for reconnections.

--
Tim Young
Elevate Software
www.elevatesoft.com

Hi Tim,

Sorry, I didn't really want to go into the pecific issues just wanted an
explanation of the log errors.

To cut a long story short, they have immense performance issues.  Users are
suddenly locked from using the appliction and speed is often very slow.
They did have an under-specced network for the number of users but have just
spent alot of money upgrading their network, switches, dedicated server for
the application and so on.  The users since claim it has got worse not
better, although we are still investigating what this perception means.

The client does not shut down the database engine, we do, so was just
interested in how the sessions work.  All users should have been out of the
system.

All tables were fine, no corruption when we checked, although we often get
index corruption in a particular table which is accessed constantly by alot
of users.  I undertand DBISAM 4 would fix this.  Unfortunately we haven't
found a window to upgrade this large application yet.

Im pretty sure we do use transactions in places, but not alot.  Is that why
you would get a general lock failure?

Just on the side I noticed the dbisam engine uses at their site upwards of
150Mb of memory.  I wouldnt imagine that would generally be an issue with a
4Gb server (of course considering the number of users there are an
applications used).

Oh yes sorry for posting this in SQL instead of server.

Thanks

Alex

"Tim Young [Elevate Software]" <timyoung@elevatesoft.com> wrote in message
news:61650192-A454-40BA-8BEA-EA9812E60878@news.elevatesoft.com...
> Alex,
>
> << We have a client who has had issues for quite some time.  They recently
> upgraded switches and moved to a dedicated server but are still
> experiencing immense problems.  We have a number of other clients of
> similar size in user terms and input wise without any apparent issues. >>
>
> What exactly is the problem that they're experiencing ?  You haven't
> actually stated what the problem is.
>
> << As I am struggling a bit to find a solution, was wondering if someone
> could help decipher what the following log items mean and how they would
> occur:
>
> 9/24/2008 12:41:57 PM Session not found, re-connection rejected [Address:
> 192.168.11.121 Version: 3.30 Request: REQUEST_RECONNECT Thread: 5768
> Session: 0]
>
> That happened for a good two minutes but after a DBISAM server shutdown
> and restart.  I presume maybe the application was still open and making
> requests after restart? >>
>
> Yes, it means that the application is still up and trying to execute calls
> to the server using a session ID that no longer exists in the DBISAM
> Database Server.  Why are they shutting down the server with applications
> still connected ?
>
> << 9/24/2008 12:34:43 PM Engine error - Access violation at address
> 004B998A in module 'dbsrvr.exe'. Read of address 000018EC [Address:
> 192.168.11.28
> Version: 3.30 Request: REQUEST_MODIFYRECORD Thread: 5480 Session: 0]
> 9/24/2008 12:34:43 PM Engine error - Access violation at address 004B998A
> in
> module 'dbsrvr.exe'. Read of address 000018EC [Address: 192.168.11.28
> Version: 3.30 Request: REQUEST_MODIFYRECORD Thread: 5240 Session: 0]
>
> Accecc violations in the serve engine always concerns me. >>
>
> Did you run a repair on the tables to ensure that there isn't any
> corruption ?
>
> << 9/24/2008 12:32:20 PM Engine error - DBISAM Engine Error # 10249
> General lock failure with the table 'BOOKING' [Address: 192.168.11.40
> Version: 3.30 Request: REQUEST_MODIFYRECORD Thread: 5956 Session:
> 555939432]
>
> There were alot of these lock failures over a 10 minute period or so. >>
>
> Is your application using transactions at all ?
>
> << This close occurred but there were no apparent logout bu user.  Should
> this normally happen? >>
>
> Sure, a session can be disconnected but not logged out.  That's how we
> allow for reconnections.
>
> --
> Tim Young
> Elevate Software
> www.elevatesoft.com
>
>

Alex,

<< To cut a long story short, they have immense performance issues.  Users
are suddenly locked from using the appliction and speed is often very slow.
They did have an under-specced network for the number of users but have just
spent alot of money upgrading their network, switches, dedicated server for
the application and so on.  The users since claim it has got worse not
better, although we are still investigating what this perception means. >>

Did you verify whether their server has any AV software running on it, or
anything else that might interfere with either the file I/O or the comms I/O
?

<< Im pretty sure we do use transactions in places, but not alot.  Is that
why you would get a general lock failure? >>

Well, you would if you start a transaction in the client application, and
then the user either kills the client application or just never commits it
due to an interruption in the comms with the DBISAM Database Server.

--
Tim Young
Elevate Software
www.elevatesoft.com

Hi Tim,

I'm very interested in this comment.  I know the users are CTRL-ALT-DEL alot
out of frustrations.  What would be the effect on the database of this if a
transaction in progress fails to complete due to being cut from the DBISAM
Database Server?  Could corruption occur?  Or would it affect other users
from accessing the table?

Thanks
Alex

">
> << Im pretty sure we do use transactions in places, but not alot.  Is that
> why you would get a general lock failure? >>
>
> Well, you would if you start a transaction in the client application, and
> then the user either kills the client application or just never commits it
> due to an interruption in the comms with the DBISAM Database Server.
>
> --

Alex,

<< I'm very interested in this comment.  I know the users are CTRL-ALT-DEL
alot out of frustrations.  What would be the effect on the database of this
if a transaction in progress fails to complete due to being cut from the
DBISAM
Database Server? >>

Nothing, it would just be rolled back and the effect would be as if the
transaction never occurred.

<< Could corruption occur?  Or would it affect other users from accessing
the table? >>

The latter - the outstanding transaction could prevent any Posts or other
transactions until it is rolled back.

--
Tim Young
Elevate Software
www.elevatesoft.com

Thanks Tim,

So just to confirm:

If a process that uses transactions is not completed due to a user
force-closing the application, then this will affect other users trying to
access those records?  How does this then right itself as a transaction
rollback or post will never be explicitly called for that focre-closed
session?

Thanks

Alex

"Tim Young [Elevate Software]" <timyoung@elevatesoft.com> wrote in message
news:BCADC787-3BC8-4570-8422-7E16E50BA53A@news.elevatesoft.com...
> Alex,
>
> << I'm very interested in this comment.  I know the users are CTRL-ALT-DEL
> alot out of frustrations.  What would be the effect on the database of
> this if a transaction in progress fails to complete due to being cut from
> the DBISAM
> Database Server? >>
>
> Nothing, it would just be rolled back and the effect would be as if the
> transaction never occurred.
>
> << Could corruption occur?  Or would it affect other users from accessing
> the table? >>
>
> The latter - the outstanding transaction could prevent any Posts or other
> transactions until it is rolled back.
>
> --
> Tim Young
> Elevate Software
> www.elevatesoft.com
>
>

Alex,

<< If a process that uses transactions is not completed due to a user
force-closing the application, then this will affect other users trying to
access those records? >>

It will only affect users trying to write (Post) to the tables involved in
the transaction - they will be blocked from doing so until the transaction
is rolled back.

<< How does this then right itself as a transaction rollback or post will
never be explicitly called for that focre-closed
session? >>

It doesn't need to be explicitly called - when the session is removed by the
DBISAM Database Server (dead session expiration time setting on the DBISAM
Database Server) it will automatically roll back any active transaction for
the session.

4.x makes this easier by introducing pinging, which will allow you to reduce
the dead session expiration time on the server and have dead sessions
removed much quicker.

--
Tim Young
Elevate Software
www.elevatesoft.com