performance « mysql « Java Database Q&A

1. How to efficiently unpublish all datas from a particular user on a blogging application?

We develop and operate a blogging application in which user data a scattered across many tables:
- Blog
- Article
- Comment
- Message
- Trackback
- 50 other tables. Users are ...

2. MySQL Prepared Statements vs Stored Procedures Performance

I have an old MySQL 4.1 database with a table that has a few millions rows and an old Java application that connects to this database and returns several thousand rows ...

3. Problems with java app and remote dbase

I'm having trouble with my java app on the database side of things. It uses connectorJ to communicate with a mysql dbase and works perfectly fine locally. When communicating with ...

4. JDBC & MySQL read performance

I really seem to have a big problem here. I'm using MySQL to store part-of-speech tagged sentences in a table. The Table looks like this:

| Field      ...

5. MySQL/Java set and get What types perform better?

Given this java code...

PreparedStatement s = prepare("SELECT ...")
ResultSet r = s.executeQuery()
s = prepare("UPDATE ...")
s.setInt(1, r.getInt(3))
s.setInt(2, r.getInt(1))
s = prepare("UPDATE ...")
s.setInt(1, r.getInt(3))
s.setInt(2, r.getInt(2))
It seems to me that MySQL JDBC would have to do ...

6. Improve performance of matrices/table aggregation and search

There is a product-feature matrix. It has thousands rows (products) and hundreds features. It has binary values that show if the product has this feature or not. So it could be ...

7. Java Social Networking, friends' activity status awareness efficient method

Assume you having a social networking website where you can have friends and also view their up to date activities. The question is, what is the most efficient way (avoiding ...

8. Comparing numbers or using prime numbers?

I'm writing a program that generates bingo card numbers. The bingo card is composed of 5 columns, 4 numbers for each column. For the first column can only contain numbers 1-8, ...

9. java mysql server getting slower

I manage my connections by JDBC connection pool (BoneCP) and I always close the connection, the preparedStatement und the ResultSet. But, when my programm is running for several days, the mysql-server ...

10. JAVA MYSQL chat performance issue with 100 users

i'm trying to develop a client-server chat application using java servlets and mysql(innoDB engine) and jetty server. i tested the connection code with 100 simulated users hitting the server at once ...

11. MySQL Data Truncation: Out of range value in Performance test

on a test for Java-MySQL-Restlet application, I write to database at 4reqs/second for 120 seconds. In this write I insert a row that has foreign key which has the same value for ...

12. "select.." in jdbc gives bad performance but not in mysql directly

If you change the query to the following similar ones, does it perform in JDBC? SELECT count(*) FROM tempDb.testTable force INDEX(samIndex) WHERE columnA <> 'N' ORDER BY columnA DESC SELECT columnA FROM tempDb.testTable force INDEX(samIndex) WHERE columnA <> 'N' ORDER BY columnA DESC SELECT left(columnA,5) FROM tempDb.testTable force INDEX(samIndex) WHERE columnA <> 'N' ORDER BY columnA DESC SELECT distinct left(columnA,5) FROM ...