c3p0 | 易学教程

【解决方案】c3p0 APPARENT DEADLOCK创建紧急线程

阅读更多关于【解决方案】c3p0 APPARENT DEADLOCK创建紧急线程

前言：最近碰见了一个非常稀奇古怪的问题，查遍google和baidu，只有2个人碰见的类似，但都还有差异，就此对c3p0产生 APPARENT DEADLOCK 的现象分析一遍现象：8月10日晚18:20分左右，当日无发布的情况下，突然抛出一个这个异常，导致系统响应变慢，之后的3天内，均产生大量的异常，系统应用oracle数据库。异常如下： Java代码 // 片段1: Caused by: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: An attempt by a client to checkout a Connection has timed out. at <span style= "color: #0000ff;" >org.springframework.orm.ibatis.SqlMapClientTemplate.execute</span> (SqlMapClientTemplate.java: 204 ) // 片段2: Caused by: java.sql.SQLException: An attempt by a client to

C3P0错误APPARENT DEADLOCK!!!解决

阅读更多关于 C3P0错误APPARENT DEADLOCK!!!解决

文章转自 http://japi.iteye.com/blog/243702 Java代码 [framework] 2008-09-18 18:36:05,109 - com.mchange.v2.async.ThreadPoolAsynchronousRunner -46651078 [Timer-18] WARN com.mchange.v2.async.ThreadPoolAsynchronousRunner - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@1c17bd4 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks! 网上说是连接池的原因.... 我的C3P0配置 Java代码 <property name="hibernate.connection.provider_class"> org.hibernate.connection.C3P0ConnectionProvider </property> <property name="c3p0.min_size">20</property> <property name="c3p0.max_size">200<

解决 APPARENT DEADLOCK!!!

阅读更多关于解决 APPARENT DEADLOCK!!!

解决 APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks 报错信息：报错信息： APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks! 在网上查了一下，大部分网友分析是c3p0造成的，我根据网友给出的参数修改了一下我的项目的参数，改好后重新启动，不再报错，稳定性需要观察。原文内容如下：最近部在生产环境的应用，系统重启后，跑了一天后就挂掉了，每天都是如此，之前一直都是挺稳定的，看了日志报出的错误是： WARN [Timer-8] ThreadPoolAsynchronousRunner.run(624) | com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@4acfc57a – APPARENT DEADLOCK!!! Complete Status: 接下来就是： java.lang.OutOfMemoryError: GC overhead limit exceeded 这个问题，搞了好几天，后来发现是C3P0的问题，这里记录一下：原c3p0参数如下: <property name=

Set SQLite connection properties in c3p0 connection pool

阅读更多关于 Set SQLite connection properties in c3p0 connection pool

问题 To specify SQLite connection properties there is org.sqlite.SQLiteConfig and it goes something like this: org.sqlite.SQLiteConfig config = new org.sqlite.SQLiteConfig(); config.setReadOnly(true); config.setPageSize(4096); //in bytes config.setCacheSize(2000); //number of pages config.setSynchronous(SQLiteConfig.SynchronousMode.OFF); config.setJournalMode(SQLiteConfig.JournalMode.OFF); SQLiteConnectionPoolDataSource dataSource = new SQLiteConnectionPoolDataSource(); Creating a connection pool

Hibernate/c3p0 connection leak

阅读更多关于 Hibernate/c3p0 connection leak

We're running a spring/hibernate/c3p0 application under load. When I reduce the c3p0 maxPoolSize to some far, far lower than the number of concurrent users, our application just hangs. There are no error messages in the log, but it doesn't proceed forward either. I expect the application to slow down, but not to stop altogether. Here is our c3p0 configuration: <bean id="coreDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close" p:driverClass="${core.jdbc.driver}" p:jdbcUrl="${core.jdbc.url}" p:user="${core.jdbc.user}" p:acquireIncrement="5" p:acquireRetryAttempts=

how to choose maximum connection pool size?

阅读更多关于 how to choose maximum connection pool size?

问题 <property name="hibernateProperties"> <props> <prop key="hibernate.c3p0.max_size">?</prop> </props> </property> is it just a random number guess ? or are there any studies that suggest to use a particular range for a specific use case? 回答1: Well, assuming that you are talking about a production system, then "random number guess" is definitely not the answer. Actually, "random number guess" is never the answer for any sort of configuration in a production environment. Same goes for "just

Is C3P0 thread-safe?

阅读更多关于 Is C3P0 thread-safe?

An interruption exception (java.lang.InterruptedException) occurs as I'm trying to perform some simple read (SELECT) operations using C3P0 on a MySQL database. The exception occurs as I increase the number of parallel threads more than 100 (I have tried with 5,10,20,60 and 100). The statement I execute is as simple as : SELECT `Model.id` FROM `Model` LIMIT 100; My connections are pooled from a ComboPooledDataSource which is configured using the following properties (see also the C3P0 manual ): c3p0.jdbcUrl=jdbc:mysql... c3p0.debugUnreturnedConnectionStackTraces=true c3p0.maxIdleTime=5 c3p0

Java Hibernate/C3P0 error: “Could not obtain connection metadata. An attempt by a client to checkout a Connection has timed out.”

阅读更多关于 Java Hibernate/C3P0 error: “Could not obtain connection metadata. An attempt by a client to checkout a Connection has timed out.”

I'm trying to get some code I was passed up and running. It appears to use the Hibernate framework. I've gotten past most of the errors tweaking the configuration, but this one has me dead stumped. It's trying to connect to two databases: gameapp and gamelog. Both exist. It seems to have issues connecting to gamelog, but none connecting to gameapp (later in the init, it connects to and loads other DBs just fine). Below, I've pasted the error and exception stack dump. I imaging there's something else in the configs, so I've also included the configuration file for that db. I know this is very

Zombie Connections to MySQL using c3p0 with tomcat

阅读更多关于 Zombie Connections to MySQL using c3p0 with tomcat

I'm using c3p0 to manage my Database Connections to MySQL. The problem is that some connections are being hold forever. I have a limit of 1000 connections, but for some unknown reason, there are 1200 open connections. To investigate it, I do this command in the tomcat server shell: netstat -n |grep 3306|grep ESTABILISHED|wc -l and it returns 1200 here is the c3p0 configuration in context.xml <Resource name="jdbc/xxxx" auth="Container" user="xxxxxx" password="xxxxx" driverClass="com.mysql.jdbc.Driver" jdbcUrl ="jdbc:mysql://xxxx:3306/xxx" factory="org.apache.naming.factory.BeanFactory" type=

should i activate c3p0 statement pooling?

阅读更多关于 should i activate c3p0 statement pooling?

问题 we are running java6/hibernate/c3p0/postgresql stack. Our JDBC Driver is 8.4-701.jdbc3 I have a few questions about Prepared Statements. I have read excellent document about Prepared Statements But i still have a question how to configure c3p0 with postgresql. At the moment we have c3p0.maxStatements = 0 c3p0.maxStatementsPerConnection = 0 In my understanding the prepared statements and statement pooling are two different things: Our hibernate stack uses prepared statements. Postgresql is