We've been fighting with a JDBC/DB2 issue for over a year now, and maybe someone here could help us.
We use Java's JDBC to access DB2. Occasionally when trying to access a BLOB in any way (get it's length, it's data, etc) we get the following cryptic message:
COM.ibm.db2.jdbc.DB2Exception: [IBM][CLI Driver][DB2/NT] SQL0423N Locator variable "1" does not currently represent any value. SQLSTATE=0F001
It seems totally random, and querying again usually works fine. I can confirm that there's no other threads using the database connection, and no other connection trying to write to the BLOB (although other connections may be reading from the same BLOB).