Re: Weird exception thrown

Thanks for the suggestion. I wrapped all "OracleClass objOracleObject = new
OracleClass();" lines of code in "using" statements. I hope this will help.
Regards,
Eddie



-----Original Message-----
From: Discussion of advanced .NET topics.
[mailto:[email protected]] On Behalf Of Marc Brooks
Sent: Monday, January 12, 2009 3:37 PM
To: [email protected]
Subject: Re: [ADVANCED-DOTNET] Weird exception thrown

Frans is 100% correct as to the cause of the problem. You MUST call Dispose
on all objects coming out of the Oracle provider. I recommend the use of the
"using" statement to insure it's always done.

Marc

On Fri, Jan 9, 2009 at 11:11, Frans Bouma <[email protected]> wrote:
>> I have an application that reads an XML file, parses it and saves its 
>> data into an Oracle database. The save is actually an insert, if the 
>> record doesn't exist or an update if the record exists. In order to 
>> figure out which operation I have to perform, I execute a select, to 
>> check whether
> the
>> record is already in the database. I build the Select SQL statement,
> create
>> an Oracle Command object with it and then call its Execute Reader method.
>> This method returns an OracleDataReader object and for that, all I 
>> care to check is to see whether it has any records. The 
>> OracleDataReader class has
> a
>> property called "HasRows" that will tell me just that.
>> I know what you are thinking: I should ask this question on a 
>> different forum, like one Oracle hosts for their ODP.NET development, 
>> but bare with
> me
>> for a second.
>> After running for 2-3 days continuously, my application starts 
>> throwing
> this
>> weird exception where it says that "Memory could not be allocated". I 
>> managed to trace the raise of the exception to the invocation of the 
>> "HasRows" property for the OracleDataReader object. The problem is 
>> that, looking at the documentation, that property is not raising any 
>> exceptions, so what the heck is going on.
>> To keep things under control, I even tried to kick in the garbage
> collection
>> (GC.Collect()) myself, every now and then. Now the exception takes 
>> longer
> to
>> be triggered, but eventually it is triggered.
>> Can anyone give me some ideas as to what else to try and figure out 
>> what
> the
>> problem is? The XML files are not really big, averaging around 100 kB
> each.
>> When the exception is triggered, I look ion the task manager and 
>> Physical Memory usage is nowhere near the top.
>> Any suggestion will be highly appreciated.
>
>        Oracle's ODP.NET is actually a wrapper around their java CLI 
> code, so it has unmanaged elements everywhere, even OracleParameter 
> objects have unmanaged elements.
>
>        This means that you have to call Dispose() on
> - OracleParameter
> - OracleDataReader
> - OracleCommand
> - OracleConnection
>
>        It's not enough to call Dispose on OracleConnection or 
> OracleCommand, nor is it enough to call Close on OracleDataReader.
>
>        If you don't do this, you'll get subtle memory leaks which 
> eventually will bring the system down.
>
>        As you're using Oracle, you can do without the select however, 
> use the MERGE statement:
> http://www.fast-track.cc/10g_166.htm
>        If you're on 9i you can use an upsert:
> http://www.praetoriate.com/oracle_tips_upserts.htm
>        If you're on an even older dinosaur (poor sod ;)), you're out 
> of luck and will have to use the select separately.
>
>        Good luck.
>
>                FB
>
>
> ----------------------------------------------------------------------
> -- Lead developer of LLBLGen Pro, the productive O/R mapper for .NET 
> LLBLGen Pro website: http://www.llblgen.com My .NET blog: 
> http://weblogs.asp.net/fbouma Microsoft MVP (C#)
> ----------------------------------------------------------------------
> --
>
>
>
>
>
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--
Marc C. Brooks
http://musingmarc.blogspot.com

NOT sent from an iPhone

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