Re: CachedRowSet Concurrency
cksanjose wrote:
I have an application that starts a new process every 15 minutes. I
create a new thread for each process so it is possible that they will
run concurrently. I have a data access layer that returns a
CachedRowSet object. When I only have 1 process running, the program
is fine. As soon as another process starts, I start getting errors in
the data access layer. I get an exception in
"com.sun.rowset.CachedRowSetImpl.populate".
What is the exact message from the exception?
What are the first few exact lines of the stack trace?
My data access layer method looks like this:
We might need an SSCCE to answer this. We certainly need to know what the
error is.
<http://www.physci.org/codes/sscce.html>
Creating an SSCCE often helps one discover an answer as they're documenting
the question.
public RowSet retrieve(String sql)
{
Connection connection = null;
Oh, please do not use TAB characters in Usenet listings!
ResultSet resultset = null;
CachedRowSet rowset = null;
Statement statement = null;
try
{
connection = Current.getConnection();
Hmm - a mysterious undocumented class with a black-box method. There's no way
this could in any way be involved with the problem.
statement =
connection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
resultset = statement.executeQuery(sql);
You may wish to read up on "SQL Injection attacks".
rowset = new CachedRowSetImpl();
rowset.populate(resultset);
resultset.close();
statement.close();
Note that exceptions could leave the ResultSet or the Statement not close()d.
What would that induce?
}
catch (SQLException sqle)
{
sqle.printStackTrace();
You should also emit the message and the SQL error code.
}
finally
{
connection = null;
What do you imagine that this accomplishes?
The variable goes out of scope anyway. The assignment accomplishes nothing,
and indeed might be optimized away.
}
return rowset;
}
--
Lew