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Poor man's approach in practice
Published on 2011-06-05 15:46:00
One day we ran into problem when an application was randomly starting using more CPU resources as usual. It continued picking more and more CPU resources from time to time. Thread dump showed many threads though we couldn't understand wich of them is
MySQL: ON DUPLICATE KEY UPDATE breaks generated key list of extended INSERT
Published on 2011-05-22 11:22:00
When extended INSERT (insert with several tuples in one query) is used with ON DUPLICATE KEY UPDATE clause and there're unique key conflict the Connector/J's Statement will return incorrect list of generated identifiers that cannot be matched with tu
How does JVM handle locks
Published on 2011-04-30 13:49:00
As we are talking about the latest version of Sun Hotspot Java Virtual Machine 1.6 there're the following three types of locks performed by JVM when you try to acquire lock from java.util.concurrent.locks.Lock implementation or enter synchronized blo
The multithreaded singleton
Published on 2011-03-22 16:57:00
We often use singleton pattern and in many case we have initialize singleton in multithreaded environment. The implementation we often use is the following:public class Singleton { private static Singleton instance; public Singleton getInstance()
The GrinderStone is nominated for Eclipse Community Awards
Published on 2011-02-02 16:43:00
The GrinderStone, an IDE for Grinder load testing scripts development, is nominated for Eclipse Community Awards 2011 in Best Developer Tool section. Any comments will be appreciated on GrinderStone nominee page. We thank our users and give them uniq
MySQL 5.5 won't start on Mac OS 10.6
Published on 2011-01-25 13:14:00
Modify the mysql.server script file using the following command : sudo /Applications/TextEdit.app/Contents/MacOS/TextEdit /usr/local/mysql/support-files/mysql.server Locate the configuration defining the basedir and set the following : basedir=/usr/l
InnoDB: strange deadlock
Published on 2010-11-07 15:18:00
One time I've noticed that some concurrent threads that perform inserts into one simple table can cause deadlock in MySQL. For example let see the table:create table TEST(id int, primary key(id)) engine=InnoDB;Note that primary key is not auto increm
JBPM concurrency issue: Action altered id
Published on 2010-10-18 16:00:00
I've worked for several days on problem when some concurrent threads create process instances from one process definition. In my environment I deploy one process definition on application startup and use this instance during whole application lifecyc
Fibonacci numbers built with SQL
Published on 2010-10-09 15:35:00
I was at work today and my friend Eugene told me that he read somewhere that one man calculates Fibonacci numbers using SQL. He asked me can I do the same and after 5-10 minutes I've got the following query:select N from ( select @f0 N, @fn:=@f
GrinderStone 2.5.3
Published on 2010-09-26 08:21:00
I've released new GrinderStone 2.5.3 version. It comes with the following features:redirect all Grinder outputs to Eclipse terminal (feature #9)compatibility with latest version of PyDev (issue #26) ability to debug Grinder scripts using nano time ca
Transparent clustering solutions
Published on 2010-09-13 17:23:00
I've spent these weekends to research and compare two transparent clustering solutions: Terracotta and Hazelcast. As a result I would choose Terracotta, a proven solution for clustering second-level cache, http sessions and distributed locks, but the
The best development strategy
Published on 2010-09-04 16:03:00
When I met my old friend in Nederlands he sad me that in the company he is working for they follow one general rule:Perform many small changes because they cause small problems instead of big changes that in any case cause big problemsI think it
Spring: case when mix of plain JDBC and Hibernate JPA will fail
Published on 2010-08-15 13:41:00
I supposed it's a new problem in Spring connection management related to all 3.X versions:when you executes query in RowMapper the next query outside of this RowMapper will fail with HibernameException.I've created SPR-7393 related to this issue
MySQL batch queries processing
Published on 2010-07-19 13:12:00
I was very surprised when we've got an issue with batch queries execution via MySQL JDBC driver: in our project we have to save big chunk of data to one table - approximately 1.5 records as one batch. It takes more than 1 minute - 86320ms! And...The