Problems extraction data

I have a java application using mysql and a strange problem is appeared. The thing is that i using the app to upload a file, the file es processed and some another data is generated and stored to mysql. Then i can extract the information related to the data uploaded.

When i made this process with a file containing 200.000 rows, the upload and the extraction do not have problems but when i have a file with 800000 rows the upload process is sucessful but the extraction give me a problem.

The problem is:
Will continue
java.sql.SQLException: Unknown character set index for field ‘16908’ received from server. Query: select field1,field2 from table where field = ? Parameters: [value]
at org.apache.commons.dbutils.QueryRunner.rethrow(QueryRunner.j ava:330)
at org.apache.commons.dbutils.QueryRunner.query(QueryRunner.jav a:213)
at org.apache.commons.dbutils.QueryRunner.query(QueryRunner.jav a:179)

The problem appears many times and finally the connection is aborted.
So, i was checking the thread and i noticed that the information is sent not as one only package, the information is sent by pieces. I decided to increase the net_write_timeout, but the problems continues.

Any idea about this problem

Thanks in advance.

I haven’t seen this before, but it looks to me like there might be invalid data stored in the table, or a character set mismatch.