How to find out the Recorset size

Question

Hi all,
I have two questions about JDBC Recordsets.
What is the most efficient way to ask the Recordset object its size?
What does fetchSize mean?
Thank you

Answer 1

I believe the best way to get the size, which I am assuming is the count of rows in the Recordset is:
rs.last();                 // jump to last row
int rowcnt = rs.getRow();  // Get the rowid
rs.beforeFirst();          // Back where we started"fetchSize" is a hint to your jdbc driver on how many rows you would like brought to your program for every round trip to and from the database. It is a value that is used to help optimize performance of your JDBC application. It is used most often to help optimize batch style processing (looping through large ResultSets) within a JDBC application.
FETCHSIZE EXAMPLE: You are looping through your ResultSet which has 100 rows using a while loop:
while (rs.next()) {
   // getxxx...
}Scenario 1) You set the fetchSize=1, jdbc will make 100 round trips to the database to get 100 rows. This would be considered inefficient (100 database calls across a network).
Scenario 2) You set the fetchSize=50, jdbc will make 2 round trips to the database to get 100 rows (2 database calls across the network).
It's really a judgement call on what you want to set the fetchSize to (if anything). Some JDBC drivers ignore it, and others have tuned other parts of their code to work best with the defaults. Still, I have had good success when changing the fetchSize value to 1000 from the default of 10 when looping through a 35,000 row ResultSet (Oracle 9i thin and oci8).
I wouldn't change fetchSize unless you are experiencing performance or resource problems with your application. Think of fetchSize as one of the tools in your toolbox that can be used if you need additional efficiencies (performance) from your application.