Question

I’m trying to implement a simple client-middleware-database architecture, where the client send the request to the middleware, then executes it on the database and finally returns the answer to the client.

To test the system I have to use the tpc-h benchmark, which is just a bench of huge queries the must be executed in order to test the response time and the throughput of the system.

The problem that I’m facing is driving me crazy: The client send 150 separated insert queries to the middleware and then the middleware processes each of them using “executeUpdate”, here a piece of my code:

Connection cc = c.getConnection();
Statement s = cc.createStatement();
int r = s.executeUpdate(tmpM.getMessage());
tmpR.add(c.getServerName()+":"+c.getDatabaseName()+": "+ r +" row(s) affected.");
s.close();
cc.close();

If I just print all the queries and I execute them manually with phpPgAdmin and then I check with pgAdmin the number if item inserted result 150 correctly, while if I use my code it doesn’t add all of them, but only a part of it.

I did a lot of debugging and it results that all the query are sent to the db (the code is executed 150 times and returns 150 times 1, the correct answer) but the result it is not correct.

Does anyone have any suggestion on how to solve it?

Thank you in advance

-g

Answer 1

Why don’t you try using transactions instead of opening/closing a connection for each of the insert statements.
From the Oracle JDBC tutorial:

"A transaction is a set of one or more statements that is executed as a unit, 
so either all of the statements are executed, or none of the statements is 
executed."

http://download.oracle.com/javase/tutorial/jdbc/basics/transactions.html