Hi Adam,

> I was just wondering if you managed to get to the bottom of this
> problem.

No, I didn't... just didn't have the time to rewrite the error classes
to forward the unknown errors.

> Recently, I've just moved one of my clients from stLocal to
> stRemote. Mostly, it's been running fine, but on some reports they
> print (larger queries) we've been having some hit and miss.
> The problem is that during the execution of a query, the application
> just 'locks up'. No error message. They have to task kill the
> application.

I don't think that it has anything to do with large or small SQL
query's.

> We're running:
>
> DBISam 4.25 b 4
> Windows 2003 Standard Server

We just have the errors at 2003 servers.

> Clients are running Windows XP
> Communication via a 100mb Lan

> I have seen some errors in the log such as:
>
> 6/4/2007 5:34:32 PM [ERROR] Engine error [Access violation at address
> 004B3E40 in module 'dbsrvr.exe'. Read of address 00000000] [Client
> Version: 4.25 User Name: amanda Address: 10.30.11.115 Encrypted: No
> Request: REQUEST_FREESTMT Thread: 5388 Session: 45416456]
>
> We aren't using any triggers or stored procedures. Just the bare
> DBSRVR.exe installation/file.

We have heavy use of triggers and stored procs.

What I found and what I think..

Because nearly all errors end with: ...REQUEST_PROCEDURE... first I
started to look at the procedures. After a long search.. and a couple
of errors I'm not sure if it's the proc itself...

I think that anything inside the communication layer is broken.
So, IMHO it won't be an issue of SQL or stored proc/trigger or anything
else...

At the time I look at the server logs. All the servers have automatic
updates enabled. I'm not sure.. in an daylight working environment I
found a lot of updates before an error occured.. so maybe..

The DBISAM server runs as a service. After an AV like yours we have to
stop/uninstall and install/restart the server.

But I have to say that we still have a couple of 2003 servers that work
without errors!.. and never had errors at 2000 servers.. exactly same
app....

If Tim would have an idea (quick&dirty snippet of code) how to forward
the unknown error to anything meaningful (madExcept..) inside the
server (I don't think that clients try to execute some invalid code) I
really would like to put these snippets in..

Because we have this error maybe every 4 weeks,.. sometimes at fridays
twice (does anyone knows if friday could be deadline of ms network
fixes?) we still wait..
End of July we'll start to port the apps to EDB.

So, it's not a solution. But, maybe it's something to think of, where
we didn't look for..

regards

ralf

Ralf,

<< If Tim would have an idea (quick&dirty snippet of code) how to forward
the unknown error to anything meaningful (madExcept..) inside the server (I
don't think that clients try to execute some invalid code) I really would
like to put these snippets in.. >>

If you simply put in madExcept, it should be able to handle grabbing the
applicable error message and state.  If you want to use something else, then
there's this procedure to look at in dbisamsv.pas:

procedure TBaseThread.ProcessException(E: Exception);

--
Tim Young
Elevate Software
www.elevatesoft.com

Hi Tim,

> << Most of the queries I have actually have about 4 seperate SQL
> statements seperated by the semicolumn all in the one SQL. They can take
> anything from 5 to 30 seconds to execute. >>
>
> Okay, that shouldn't cause an issue.  Are you using the
> TDBISAMSession.OnRemoteSendProgress/OnRemoteReceiveProgress event
> handler(s) at all ?

No. I am however using the OnQueryProgress event on the TDBISamQuery.

> Thanks.  The issue is one where every time the actual SQL statement is run
> in isolation, it doesn't have an issue.  So, I can't reproduce anything
> after the fact, at least not yet.

I understand. It's hard to diagnose problems that you can't see for
yourself.

Best Regards

Adam.

Hi Ralf,

Out of curiosity - do you use live queries in the applications that you're
having problems with? (I noticed that build 3.24 fixed an Access Voilation
problem when using RequestLive in Queries, and I'm just wondering if that is
the common factor herewith this problem too).

> The DBISAM server runs as a service. After an AV like yours we have to
> stop/uninstall and install/restart the server.

Thankfully we're not having that sort of problem. Ours shows AV's in the log
file (and from what I can gather, people need to terminate their instance of
the application, and restart it), but we haven't had to stop and restart the
server yet.

> But I have to say that we still have a couple of 2003 servers that work
> without errors!.. and never had errors at 2000 servers.. exactly same
> app....

Can I have one of those servers please?  

> Because we have this error maybe every 4 weeks,.. sometimes at fridays
> twice (does anyone knows if friday could be deadline of ms network
> fixes?) we still wait..
> End of July we'll start to port the apps to EDB.

Mine are more common.... happening a number of times throughout a day.

I've just dropped the server back to 4.24 to see if that makes any
difference.


Cheers

Adam.

Hi Adam,

> Out of curiosity - do you use live queries in the applications that
> you're having problems with? (I noticed that build 3.24 fixed an
> Access Voilation problem when using RequestLive in Queries, and I'm
> just wondering if that is the common factor herewith this problem
> too).

yes, we have all kind of querys, live, canned.. we do inserts, edit on
live querys. Heavy use of stored procs, a little table based edit's and
major part is just send the query to the server where we have a lot of
triggers..

> > But I have to say that we still have a couple of 2003 servers that
> > work without errors!.. and never had errors at 2000 servers..
> > exactly same app....
>
> Can I have one of those servers please?  




> Mine are more common.... happening a number of times throughout a day.

indeed a strange problem..
did you try madexcept at client side? if just a client restart would
fix that error,.. sounds like the client is responsible for this error..

> I've just dropped the server back to 4.24 to see if that makes any
> difference.

in our case with the server errors I disabled at one customers net (24
clients) automatic updates at server. Since 10 days no errors.. every
manual update I write down all the fixes that arrived from MS..
I don't think I'll find anything useful...  but maybe..

So, I'll look forward to EDB... to keep my customers happy..

regards
ralf

Hi Ralf,

>> Mine are more common.... happening a number of times throughout a day.
>
> indeed a strange problem..
> did you try madexcept at client side? if just a client restart would
> fix that error,.. sounds like the client is responsible for this error..

I haven't actually purchased madexcept, however the AV's aren't happening at
the client end - they're happening in the log on the server. (The client
just gets a lockup of the application, and has to kill the process).


> in our case with the server errors I disabled at one customers net (24
> clients) automatic updates at server. Since 10 days no errors.. every
> manual update I write down all the fixes that arrived from MS..
> I don't think I'll find anything useful...  but maybe..

One can only try I guess.

> So, I'll look forward to EDB... to keep my customers happy..

Unfortuantly, that's not an option for me just at this point in time. I've
rolled the server app back a version to see if this makes any difference.
(So far no AV's on the servers log, but it's only been a couple of hours).

Cheers

Adam.

Adam,

<< The problem is that during the execution of a query, the application just
'locks up'. No error message. They have to task kill the application. >>

Quick question - what is the TDBISAMSession.RemoteTimeout property set to
for the client application's remote session ?  Also, did you define an event
handler for the TDBISAMSession.OnRemoteTimeout event ?

It might have something to do with the client timing out while waiting for a
response during the query execution.

--
Tim Young
Elevate Software
www.elevatesoft.com

Good Morning Tim,

> << The problem is that during the execution of a query, the application
> just 'locks up'. No error message. They have to task kill the application.
>  >>
>
> Quick question - what is the TDBISAMSession.RemoteTimeout property set to
> for the client application's remote session ?

I have tried both 300 and 60 on this property, neither making a difference.

> Also, did you define an event handler for the
> TDBISAMSession.OnRemoteTimeout event ?

Originally no, but 2 weeks ago I did put an event here to show a message to
say that it had triggered (so the users could report the message to help
with troubleshooting).

> It might have something to do with the client timing out while waiting for
> a response during the query execution.

I did think of that, which is why I changed those values about a fortnight
ago, unfortuantly with no luck.

I dropped the server back to 4.24 at the start of the week to see if that
makes a difference. Since doing it, we have had less problems (but not
totally eliminated)..

Only one machine locks up now, and it took two and a half days for the first
AV's to show up in the DBISam log since changing back a version.

Cheers

Adam.

Adam,

<< I dropped the server back to 4.24 at the start of the week to see if that
makes a difference. Since doing it, we have had less problems (but not
totally eliminated).. >>

I know it's been fashionable among several customers that dropping back to
prior versions reportedly solves issues, but there's no substance to such
statements as far as I know.   Whatever is causing these types of errors has
probably been in there for a long time, the reason being that I simply have
never been able to reproduce any of it.  If I could reproduce such AVs, or
if I ever experienced them here in either our use of the database server or
the automated testing, it would be fixed immediately.

--
Tim Young
Elevate Software
www.elevatesoft.com

Adam,

One other thing - are you running the database server with or without the
user interface/system tray functionality ?

--
Tim Young
Elevate Software
www.elevatesoft.com