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https://issues.apache.org/jira/browse/DBCP-377?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13222645#comment-13222645
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Mark Thomas commented on DBCP-377:
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I'm not aware of any known issues with idle object eviction.
It shouldn't be the app holding on to an idle connection too long before
returning it since the removeAbandoned* settings will handle that after 5
minutes.
I assume that you are 100% certain that the middleware layer is dropping the
connections after 1 hour.
Can you provide some idea of the frequency this occurs? E.g x failures per hour
and y connections borrowed per second. I'm trying to understand how rare the
issue is.
Some things to check:
1. What version of commons-pool are you using and if it isn't the latest does
upgrading fix the issue?
2. numTestsPerEvictionRun=32 seems too high if maxIdle=20
3. Is it possible that the app could obtain a connection from the pool but
never use it? That would reset DBCP's idle timer but not the middleware layer's.
> Dbcp Idle Check Mechanism Doesn't Work
> --------------------------------------
>
> Key: DBCP-377
> URL: https://issues.apache.org/jira/browse/DBCP-377
> Project: Commons Dbcp
> Issue Type: Bug
> Affects Versions: 1.4
> Environment: Linux mysql 5.1.4
> Reporter: yixin he
> Priority: Critical
>
> Using :commons-dbcp-1.4.jar version
> we use a distributed data access layer for Database Sharding with mysql
> our web servers use mysql jdbc driver 1.5.4 to connect to this middleware
> layer with F5 between them for load balance.
> the middleware layer will discard db links that idle for longger than 1
> hour,and our dbcp configures to close links that idle for
> longger than 30 minutes.
> here we occurred exceptions as follows:
> {code}
> java.net.SocketException
> MESSAGE: Broken pipe
> STACKTRACE:
> java.net.SocketException: Broken pipe
> at java.net.SocketOutputStream.socketWrite0(Native Method)
> at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
> at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
> at
> java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
> at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
> at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2637)
> at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1554)
> at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1665)
> at com.mysql.jdbc.Connection.execSQL(Connection.java:3176)
> at
> com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1153)
> at
> com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:794)
> ....
> at
> org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
> at
> org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
> {code}
> it seems that there are times when the links get from pool they have already
> been broken,we know that they are forcely closed by the middleware layer、but
> as dbcp idle check more frequently than the middleware layer(30m to 60m). How
> can this happen as the idle links
> should have been closed by dbcp first. Are there any problems for the dbcp
> idle check Mechanism？
> our dbcp configurations are as follows
> {code}
> <property name="maxActive"><value>20</value></property>
> <property name="initialSize"><value>1</value></property>
> <property name="maxWait"><value>60000</value></property>
> <property name="maxIdle"><value>20</value></property>
> <property name="minIdle"><value>5</value></property>
> <property name="removeAbandoned"><value>true</value></property>
> <property name="removeAbandonedTimeout"><value>180</value></property>
> <property
> name="connectionProperties"><value>clientEncoding=GBK</value></property>
> <property
> name="timeBetweenEvictionRunsMillis"><value>60000</value></property>
> <property
> name="minEvictableIdleTimeMillis"><value>1800000</value></property>
> <property name="testWhileIdle"><value>true</value></property>
> <property name="testOnBorrow"><value>false</value></property>
> <property name="testOnReturn"><value>false</value></property>
> <property name="validationQuery"><value>SELECT
> @@SQL_MODE</value></property>
> <property name="numTestsPerEvictionRun"><value>32</value></property>
> {code}
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