How to set the fetch size for a ResultSet object?

Question

Connection con  = getConnection();
Statement stmt = con.createConnection();
ResultSet res = stmt.executeQuery("select * from table");
//res.setFetchSize(?);
while (res.next)
res.get....
}I do not know the number of rows .
How can I set the fetch size for the ResultSet object?
I try
res.last();
res.setFetchSize(res.getRow()/2);
res.beforeFirst();
while (res.next)
res.get....
}but it's so slow if there are 6000 rows.
How can I set the fetch size for the ResultSet object more effectible?
And what is the best number to set the fetch size?

Answer 1

The fetch size defaults to a standard number. It is unlikely that it will be any faster if you set it unless you only plan to read a small number of rows.
i.e. if you are going to read all the rows, you need to read all the rows no matter what.
Unless the system has set the fetch size to 1 changing it will not be faster.
Depending on the row length, reading in 6000 rows is going to take a long time. You could try using a cpu profiler to improve performance.
Do you really need to read everything in every row?