JDBC with MySQL really slow, don't know why

Question

Hi guys,

I have a problem with a really slow connection between my Java code and a MySQL Database. I don't know where the bottle neck is.

My program is more or less a chatbot. The user types something in, my program splits the sentence into words and sends it word per word to the database. If it finds something there, the user gets an output. The database is on an external Server, but I also tried to connect to a pc next to me. Both is slow.

I tried the connection once at another place then where I normally work and there it was fast, most of the time.

My SQL Code:

SELECT info.INFORMATION FROM INFORMATION info, INFO_SCHLUESSEL sch
WHERE LCASE(sch.SCHLUESSELWORT) LIKE '" + input + "%' AND info.ID_INFO = sch.ID_INFO
Order BY info.PRIORITAET DESC LIMIT 1;

(just remembered, if it helps to understand the sql code:
schluessel = key
Schluesselwort = key word
prioritaet = priority)

My Java Database Code is more or less standard stuff:

String driver = "com.mysql.jdbc.Driver";
String dbase = "jdbc:mysql://bla";
String dbuser = "bla";
String dbpw = "bla";

Class.forName(driver);
Connection con = DriverManager.getConnection(dbase, dbuser, dbpw);
Statement stmt = con.createStatement();

ResultSet rs = stmt.executeQuery(query);
while (rs.next())
{
ergebnis = rs.getString("info.INFORMATION");
}

rs.close();
stmt.close();
con.close();

edit:

I have tried this DBCP for a while now, and I can't seem to get it to work. It seems to be as slow as the old connection. This is the example provided by the website that I use:

GenericObjectPool connectionPool = new GenericObjectPool(null);
ConnectionFactory connectionFactory = new DriverManagerConnectionFactory("jdbc:mysql://bla", "bla", "bla");
PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(connectionFactory,connectionPool,null,null,false,true);
PoolingDriver driver = new PoolingDriver();
driver.registerPool("example",connectionPool);
Connection conn = DriverManager.getConnection("jdbc:apache:commons:dbcp:example");

Answer 1

I suspect that it's the connection setup that is causing the problem. It would be worth timing how long this takes:

Connection con = DriverManager.getConnection(dbase, dbuser, dbpw);

and if so, check out Apache Commons DBCP, which allows you to pool database connections.

Answer 2

Well I think this warrants a discussion on the design.There are a few things which you can do in order to improve the performance. Since you are not persisting anything here, its better to preload all the data in memory in some custom java object, a map, list or whatever and then do an in-memory lookup for the word and get the results. Another approach could be to use a batch statement so that you dont go ahead and create and release connections for each word. Oh and if using batch statements make sure you set the batch size to an appropriate number, preferably a prime number