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c3p0 pool is not shrinking
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Closed 8 years ago.
I am using c3p0 connection pool with spring (with plain jdbc, NO hibernate). Here is my config
<bean id="myDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<property name="driverClass" value="${jdbc.driver}"/>
<property name="jdbcUrl" value="${jdbc.url}"/>
<property name="user" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
<property name="acquireIncrement" value="3"/>
<property name="minPoolSize" value="3"/>
<property name="maxPoolSize" value="25"/>
<property name="maxStatementsPerConnection" value="0"/>
<property name="numHelperThreads" value="6"/>
<property name="testConnectionOnCheckout" value="false" />
<property name="testConnectionOnCheckin" value="false" />
<property name="idleConnectionTestPeriod" value="10"/>
<property name="preferredTestQuery" value="select curdate()"/>
<property name="maxIdleTime" value="5" />
<property name="unreturnedConnectionTimeout" value="5" />
<property name="debugUnreturnedConnectionStackTraces" value="true" />
</bean>
I do see that connection pool hits max value of 25 connections but there shrinks back never shrinks back when load reduces.
I am missing some config here???
Please see the config parameters maxIdleTime and maxIdleTimeExcessConnections.
If you want to aggressively pare back pool size when load lightens, set a short maxIdleTimeExcessConnections. Leave just plain maxIdleTime fairly long, so you don't needlessly churn through Connections once your pool has hit minPoolSize.
If you don't care so much, then just set maxIdleTime and eventually the pool will shrink as idle Connections expire. But for reasonable values of maxIdleTime, this will happen slowly.
If neither maxIdleTime nor maxIdleTimeExcessConnections (nor maxConnectionAge) are set, these values all default to zero, meaning Connections never expire, and the pool will only shrink as Connections break and fail tests.
Related
I am making custom effects with Direct2D, based on Microsoft Learn page. The problem is that, I wanted to make a Direct2D effect which support a variable input count, like Direct2D Composite Effect, while the XML registration string used for ID2D1Factory1::RegisterEffectFromString seemed to take fixed <Input> properties. What should be done in XML registration string?
My XML is almost the same as one from Microsoft Learn page. Still I will provide mine.
auto xml_AxisRotation = XML(
<?xml version='1.0'?>
<Effect>
<!--System Properties-->
<Property name='DisplayName' type='string' value='MultiInput Effect'/>
<Property name='Author' type='string' value='Nan_ok'/>
<Property name='Category' type='string' value='None'/>
<Property name='Description' type='string' value='asdfasdfasdf'/>
<Inputs>
<Input name='Source1'/>
<Input name='Source2'/>
//...?
</Inputs>
<!--Custom Properties go here-->
<Property name='Mode' type='int32'>
<Property name='DisplayName' type='string' value='Mode'/>
<Property name='Default' type='int32' value='1'/>
</Property>
</Effect>
);
I once deliberately omitted the whole <Input> part, but it failed to perform; E_INVALIDARG has been returned.
The XML registration and actual Direct2D effect's input taking worked differently. By proper implementing ID2D1EffectImpl::SetGraph and calling ID2D1Effect::SetInputCount, I was able to set variable numbers of target.
It seemed ok to leave <Inputs> with no <Input> property. here is my XML example.
auto xml_AxisRotation = XML(
<?xml version='1.0'?>
<Effect>
<!--System Properties-->
<Property name='DisplayName' type='string' value='MultiInput Effect'/>
<Property name='Author' type='string' value='Nan_o'/>
<Property name='Category' type='string' value='None'/>
<Property name='Description' type='string' value='asdfasdfasdf'/>
<Inputs> </Inputs> <!--Leaving like this is ok-->
<!--Custom Properties go here-->
<Property name='Mode' type='int32'>
<Property name='DisplayName' type='string' value='Mode'/>
<Property name='Default' type='int32' value='1'/>
</Property>
</Effect>
);
Hi I have been using Spring AMQP with connection obtained from CachingConnectionFactory with the properties being shown below
<bean id="connectionFactory"
class="org.springframework.amqp.rabbit.connection.CachingConnectionFactory">
<constructor-arg value="rabbit-server-fqdn" />
<property name="virtualHost" value="some-vhost" />
<property name="username" value="username" />
<property name="password" value="password " />
<property name="channelCacheSize" value="25" />
</bean>
Now i need to change my mode to Connection as i need to check open connection
<bean id="connectionFactory"
class="org.springframework.amqp.rabbit.connection.CachingConnectionFactory">
<constructor-arg value="rabbit-server-fqdn" />
<property name="virtualHost" value="some-vhost" />
<property name="username" value="username" />
<property name="password" value="password " />
<property name="cacheMode" value="CONNECTION" />
<property name="channelCacheSize" value="25" />
</bean>
So
Q1. Will channelCacheSize will work ?
Q2. what will be default connection pool size in CachingConnectionFactory ?
Q3. Do i need to set additional property ?
The CHANNEL is better, because you don't need to create a new connection for each call, but reuse a shared one.
The Reference Manual has plenty of facts on the matter. One of them is when do you really need CONNECTION mode:
The use of separate connections might be useful in some environments, such as consuming from an HA cluster, in conjunction with a load balancer, to connect to different cluster members.
The shared connection is still can be traced for open/close state via ConnectionListener injected into that CachingConnectionFactory.
I have a use case where when the connectivity to rabbitmq goes down I need to manage the messages in different way.
I have a logic
RabbitTempate template // get template using API call
template.setReplyTimeout(10000);
template.convertAndSend(message);
But the problem is when the rabbitmq server connectivity goes down Spring AMQP automatically waits for connectivity to get resolved for 5 min
But because of that the client thread calling that particular logic waits for 5 min .
Is there any way i can change it , I am using CachingConnectionFactory
<bean id="connectionFactory"
class="org.springframework.amqp.rabbit.connection.CachingConnectionFactory">
<constructor-arg value="rabbit-server-fqdn" />
<property name="virtualHost" value="vhost" />
<property name="username" value="username" />
<property name="password" value="password" />
<property name="cacheMode" value="CONNECTION" />
<property name="channelCacheSize" value="25" />
</bean>
Is there any way I can override these settings from 5 min so that client API does not need to wait for such huge amount of time ?
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="${db.driver}"/>
<property name="url" value="${db.jdbcurl}"/>
<property name="username" value="${db.username}"/>
<property name="password" value="${db.password}"/>
</bean>
<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource" ref="datasource">
<property name="hibernateProperties">
<value>
hibernate.c3po.max_size=20
</value>
</property>
</bean>
Hi guys, I have above set up for my application. We use DBCP connection pool. However, We have also set c3po properties in my hibernate SessionFactory.
My observation from the log suggests that DBCP overwrite the C3P0 properties in hibernate.
In this situation, is c3p0 property complete redundant? If yes, does it take up unnecessary resources in any way?
Thanks.
Our Webflow (2.3.1) application is claiming a lot of memory for each new flow that we open through the browser.
The screenshot below shows our application's memory use. When the application starts it takes an initial 400 Mb. After that we open 4 individual, identical Webflow TEST pages in the browser which each claim about 90Mb of extra memory..
Each test page is started from its own simple flow definition:
<?xml version="1.0" encoding="UTF-8"?>
<flow xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.springframework.org/schema/webflow"
xsi:schemaLocation="http://www.springframework.org/schema/webflow
http://www.springframework.org/schema/webflow/spring-webflow-2.0.xsd" start-state="start">
<view-state id="start" view="test/test1">
</view-state>
<end-state id="end"/>
<bean-import resource="../flow-beans.xml"/>
</flow>
The JSP test pages are also very simple, just empty with one line of text.
When we currently set the JVM memory to 1.5Gb the application eventually crashes on the server with OutOfMemoryExceptions after opening about 15 different flows. 1.5 Gb seems a bit much, regarding the low complexity of our screens..
We are wondering if the amount of memory Webflow seems to claim for these simple flows/pages is expected and if we should therefore just assign more memory to the server JVM. If not, we would like to know how we can decrease this memory usage.
Below is our entire webflow configuration.
We have tried adding a flow-execution-repository tag and played around with the max-executions-snapshots and max-executions values, but even the most conservative settings don't change the memory usage we are seeing.
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:webflow="http://www.springframework.org/schema/webflow-config"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/webflow-config
http://www.springframework.org/schema/webflow-config/spring-webflow-config-2.3.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">
<!-- Launches new flow executions and resumes existing executions. -->
<webflow:flow-executor id="flowExecutor" flow-registry="flowRegistry">
</webflow:flow-executor>
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location" value="classpath:our.properties" />
<property name="placeholderPrefix" value="$xxxx"></property>
</bean>
<tx:annotation-driven transaction-manager="$xxxx{txManager}" />
<!-- Creates the registry of flow definitions for this application -->
<webflow:flow-registry id="flowRegistry" flow-builder-services="flowBuilderServices">
<webflow:flow-location-pattern value="classpath:flows/**/*-flow.xml" />
</webflow:flow-registry>
<bean id="viewFactoryCreator" class="org.springframework.webflow.mvc.builder.MvcViewFactoryCreator">
<property name="viewResolvers" ref="viewResolver" />
</bean>
<bean id="expressionParser" class="org.springframework.expression.spel.standard.SpelExpressionParser">
<constructor-arg name="configuration">
<bean class="org.springframework.expression.spel.SpelParserConfiguration">
<constructor-arg name="autoGrowCollections" value="true" />
<constructor-arg name="autoGrowNullReferences" value="false" />
</bean>
</constructor-arg>
</bean>
<bean id="webflowExpressionParser" class="org.springframework.webflow.expression.spel.WebFlowSpringELExpressionParser">
<constructor-arg name="expressionParser" ref="expressionParser" />
</bean>
<webflow:flow-builder-services id="flowBuilderServices" view-factory-creator="viewFactoryCreator" validator="validator" expression-parser="webflowExpressionParser"/>
<bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean" />
<bean id="projectVersion" class="our.company.versions.ProjectVersionUtil">
<property name="xxxxVersion" value="$xxxx{xxxx.version}" />
<property name="systemConfigurationDao">
<ref bean="SystemConfigurationDao"/>
</property>
</bean>
</beans>
When Spring Web Flow starts a new flow it basically constructs a new BeanFactory which loads the xml file and imports any additional xml files. The newly constructed BeanFactory has the context of the DispatcherServlet as its parent.
Now the problem with this is that a the bean factory constructs instances of all the beans even those defined in imported XML files.
<bean-import resource="../flow-beans.xml"/>
If there are a lot of beans in there those will be duplicated for each flow instance. In general you don't want your all of your beans duplicated and stored in the users sessions.
Remove the singleton beans from the flow-beans.xml and put them in the normal application context, they are still referable from within the flow definition. Or you could simply add the flow-beans.xml to the list of files loaded at startup of your application.