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trouleshooting help needed- query sometimes resulting in invalid data

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jen89

Programmer
Aug 16, 2001
105
US
I am at my wits end and need some troubleshooting help. I am writing a dynamic reporting tool. Users can pick a number of search criteria and output criteria, then hit search and get a grid filled with their results. It is fairly dynamic - the available output criteria are driven by a database table that contains the field name, the table name, the description of the criteria, and other relevant info.

This program has worked well for months. Last week, I started seeing some strange behavior. When the user hits search, the grid fills with records as it should. The first couple hundred records are correct, but all records after this show little squares, like invalid characters in Excel, where the data should be. (?????). The sql is definitely correct, as I can run it through other tools. The squares are actually stored that way in the datatable, so I don’t thing it is the display grid.

The weird thing is that a couple of the columns will still show the correct data, all the way down the dataset, while others will show the squares. Stranger yet, if certain output criteria are selected, all the records come back correctly. There doesn’t seem to be much of a pattern to this.

We have things set up so that all developers are running the code on their own machines, and we release the code up to a test server at the customer’s site. The test site works fine. All developers, even those with code older than the last test release, exhibit the problem. Nonetheless, I pulled down all of the code from the test machine, where it worked, and created a new project on my machine to try to roll back to the working version. The code did not work on my machine. So essentially, this problem started up all of the sudden, on everyone’s machine, except the test machine. It also doesn’t matter whether I point the app to the dev, test, or production database instance (Oracle), it all works on the test machine but not on ours.

I don’t know where to look or who to ask.
I figure there are a few places that this problem could be occurring.
1) code – why do even the old versions of code have the problem, while the test server with a newer version works? Why didn’t rolling back the code to the working test server code fix the problem?
2) Database – why does the actual sql run fine? Why would the problem show up on all machines except test, even though we tried pointing them at the same database?
3) Machine setup – why did all the machines simultaneously stop working (except customer machines)? Why does varying the output criteria selected change the manifestation of the problem?

The customers did do routine maintenance to all application and database servers last week, around the time this stopped working. Naturally, this makes me suspicious, but how would something they did to their servers stop our stuff from working? I am completely desperate, so even if you have no idea what this could be, please throw out any ideas that I could at least investigate. Thanks so much for reading this huge post!
 
Hi Jen,

Did any Windows updates or patches get installed on all the machines, except your dev. server? If any were installed, it may explain this strange behaviour. Just tossing some ideas out there.

HTH,

Keith
 
Thanks so much for your ideas! It ended up that a different program that some of us installed changed the NLS_LANGUAGE setting in the registry, but it only affected queries using the system.data.oracleclient managed provider. Wow, that one had me running in circles for a while there! Thanks again,
 
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