Breaking connection to Oracle

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belitski

Breaking connection to Oracle

Post by belitski » 13 Jun 2014, 08:30

Hello everybody,

i write it with the hope, that somebody had similar problem.
Our CTD151 Application was very stable for long time (many years).
Without any changes in the program we have since some weeks by customer sporadic breaks of connection to Oracle.
At least this is our current understanding. What we get are SQL errors from any place in the application.
Reproducible are errors when, for example, a grid with big number of lines is scrolled and there are additional queries for each fetched line.
If the cursor for this additional query is connected at the higher level and is executed on fetch of every record, there is always an error that happens
each time on another record (in this sense it is sporadic). Sometimes it can be scrolled to the end without crash. The log from sqlora32 is not helpful.
If we introduce connect-disconnect logic for every such additional query, it helps. But this is not a solution - there are too many such places in the project.
It looks for us as network problems, but any attempt to find it out from any sort of logs was unsucsessful.
We also cannot reproduce these errors in our environment.

Any idea is highly appreciated.
Vladimir

frevelundfey

Re: Breaking connection to Oracle

Post by frevelundfey » 16 Jun 2014, 08:45

Hi Vladmir,
there are a lot of possible reasons for this behaviour:
- the application reaches the limit of open cursors in Oracle
- if you use resultset mode - there could be a problem with the front end resultset files
- ...

It would be helpful to know what kind of error occurs.
E.g. the sqlerror-number.

Regards Thomas

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Charlie
Canada
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Joined: 07 Mar 2017, 18:52
Location: Fredericton, New Brunswick, Canada

Re: Breaking connection to Oracle

Post by Charlie » 16 Jun 2014, 11:40

Maybe a silly question, but what the heck...

Have you noticed if the errors happen only for users with wireless network connections ?

belitski

Re: Breaking connection to Oracle

Post by belitski » 16 Jun 2014, 12:03

Hi Thomas,

thank you for answering.

The error comes sporadic and it says:
Cannot create a front-end result set.
Remedy: Verify that there is sufficient memory at the client workstation.
Verify that the FILES configuration parameter of your operating system is set high enough to support multiple files.

There are many clients by customer and they mainly have Windows 7 computers. They all have a mapped drive where our application is installed and they start application login module over a link.
All necessary files like EXE and APDs are loaded then over network onto the client. Every client has its own Oracle client installation.
The TEMP directory is on the client side and we can see, that when error comes the FRS files disappear. There are not too many of them - about 10-15 files, one of which grows while the user scroll down the grid.
This file is not very big, about 1-2 MB.
This configuration has worked fine a number of years. Nothing was changed from the application side. The IT says they also did not change anything.
An example with grid scrolling is well reproducible, but the same error comes sporadic from any other place in the program.

Vladimir

frevelundfey

Re: Breaking connection to Oracle

Post by frevelundfey » 18 Jun 2014, 12:08

Hi Vladimir , we had a similar issue with frs-files and suddenly not properly working application. They reason was an update of the antivirus software which blocked frs files.
All other reasons I know you already considered.
Regards Thomas

belitski

Re: Breaking connection to Oracle

Post by belitski » 20 Jun 2014, 09:39

Hello,

@Charlie: no, clients do not use wireless

@Thomas: thank you very much for info, we'll try to check it

regards,

Vladimir

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