ResultSet.last() problem

Question

Hi All,
I am having proble with the ResultSet.last() method.
The query contains about 25000 records.
Methods next() and prev() works fine.
But last() hung.
The client program is running on different machine from the Oracle database Server.
Bellow is about what I did.
==========================================
protected Statement stmt = null;
protected ResultSet rset;
stmt = conn.createStatement( ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY );
rset = stmt.executeQuery( "Select * from mytable" );
rset.setFetchSize( 10 );
rset.last();
// Never got here.
stmt.close();
conn.close();
==========================================
Any help is appreciated!
Gwowen

Answer 1

Here is a possible reason why that would hang:
To find the "last" record, the database would have to read through all 25,000 records and send them to your program. This would take a long time, since you told it (setFetchSize(10)) to only send 10 records at a time over the network. So perhaps you just didn't wait long enough. Or perhaps something in the network timed out.
You often see this method posted as a way to find the size of a ResultSet on this forum. However (as you see) it isn't the most efficient in many cases. What you posted is probably your cut-down program -- thank you for not posting 1,000 lines of code -- but an easy way to find the size of that query without actually having to execute it is to execute "Select count(*) from mytable". It returns only 1 row with 1 column, containing the number you want.