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From Arthur Blake <arthur.bl...@gmail.com>
Subject Re: SQLTransientConnectionException with BLOB reads
Date Sat, 18 Aug 2007 14:37:02 GMT
Yes, that was the problem.

If I change my code to keep the Connection open after I have a Blob in 
hand, and then read the Blob it works.

It appears that also the ResultSet and PreparedStatement I used to fetch 
the Blob must also remain open until I'm done reading the Blob.

That seems reasonable.

Sorry that I didn't see that in the release notes (they are quite big) 
as I didn't even realize I was doing this in the code... (my Lob reading 
code was buried in some utility classes.)

I believe the Release note entry for this is DERBY-2729 .

Paraphrasing:  "Now Blobs and Clobs store their data in temporary files..."

Can I assume that Blob reads (especially for smaller Blobs) will be 
slower now because they will have to be copied to temp files?

Thank you very much.

Arthur Blake

Øystein Grøvlen wrote:
> Arthur Blake wrote:
>> Hello, I have been using Apache Derby for a few months, and 
>> it has been working quite well for me.
>> I upgrade to just after the release came out, and I have been 
>> testing it out with my application.
>> It seems to work fine, except when I read some BLOB fields from the 
>> database, this Exception is thrown:
>> java.sql.SQLTransientConnectionException: No current connection.
>>   at 
>> org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown 
>> Source)
>>   at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
>>   at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
>>   at org.apache.derby.impl.jdbc.Util.noCurrentConnection(Unknown Source)
>>   at org.apache.derby.impl.jdbc.EmbedConnection.checkIfClosed(Unknown 
>> Source)
>>   at org.apache.derby.impl.jdbc.EmbedBlob.checkValidity(Unknown Source)
>>   at org.apache.derby.impl.jdbc.EmbedBlob.getBytes(Unknown Source)
>> ......
> Are you accessing the Blob after the Connection from which is was 
> obtained has been closed?  As described in the release notes for 10.3, 
> it now required that the Connection is still open in order to access the 
> Blob.  In 10.2, small Blobs may be accessed after the connection is 
> closed, but not larger Blobs.
> Please, check whether the Connection should still be open when the 
> failure occurs.  If not, is it possible for you to change your 
> application to keep the connection open as long as needed?
> -- 
> Øystein

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