Too many connections , tomcat7 on AWS EC2

问题

I signed up for a new AWS free account, and I am trying to to connect the Tomcat to the RDS database through JNDI Pool connection. The war deployed on the Beanstalk is the default one (which does not have any database connection or queries)

Here is how my context.xml looks like

<Context>

<WatchedResource>WEB-INF/web.xml</WatchedResource>

<!-- Uncomment this to disable session persistence across Tomcat restarts -->
<Manager pathname="" />

<!-- Uncomment this to enable Comet connection tacking (provides events
     on session expiration as well as webapp lifecycle) -->
<!--
<Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />
-->
<Resource name="jdbc/web"
      auth="Container"
      type="javax.sql.DataSource"
      factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
      testWhileIdle="true"
      testOnBorrow="true"
      testOnReturn="false"
      validationQuery="SELECT 1"
      timeBetweenEvictionRunsMillis="30000"
      maxActive="10"
      maxIdle="5"
      minIdle="1"
      removeAbandonedTimeout="60"
      removeAbandoned="false"
      logAbandoned="true"
      minEvictableIdleTimeMillis="30000"
      closeMethod="close"
      jdbcInterceptors="org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer"
      username="root"
      password="password"
      driverClassName="com.mysql.jdbc.Driver"
      url="jdbc:mysql://aamhszwo5p1rrw.cf7vbk9ataaz.us-west-2.rds.amazonaws.com:3306/broadleaf"/>
<Resource name="jdbc/storage"
          auth="Container"
          type="javax.sql.DataSource"
          factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
          testWhileIdle="true"
          testOnBorrow="true"
          testOnReturn="false"
          validationQuery="SELECT 1"
          timeBetweenEvictionRunsMillis="30000"
          maxActive="10"
          maxIdle="5"
          minIdle="1"
          removeAbandonedTimeout="60"
          removeAbandoned="false"
          logAbandoned="true"
          minEvictableIdleTimeMillis="30000"
          closeMethod="close"
          jdbcInterceptors="org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer"
          username="root"
          password="password"
          driverClassName="com.mysql.jdbc.Driver"
          url="jdbc:mysql://aamhszwo5p1rrw.cf7vbk9ataaz.us-west-2.rds.amazonaws.com:3306/broadleaf"/>
<Resource name="jdbc/secure"
          auth="Container"
          type="javax.sql.DataSource"
          factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
          testWhileIdle="true"
          testOnBorrow="true"
          testOnReturn="false"
          validationQuery="SELECT 1"
          timeBetweenEvictionRunsMillis="30000"
          closeMethod="close"
          maxActive="10"
          maxIdle="5"
          minIdle="1"
          removeAbandonedTimeout="60"
          removeAbandoned="false"
          logAbandoned="true"
          minEvictableIdleTimeMillis="30000"
          jdbcInterceptors="org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer"
          username="root"
          password="password"
          driverClassName="com.mysql.jdbc.Driver"
          url="jdbc:mysql://aamhszwo5p1rrw.cf7vbk9ataaz.us-west-2.rds.amazonaws.com:3306/broadleaf"/>
<Resource name="jdbc/event"
          auth="Container"
          type="javax.sql.DataSource"
          factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
          testWhileIdle="true"
          testOnBorrow="true"
          testOnReturn="false"
          validationQuery="SELECT 1"
          timeBetweenEvictionRunsMillis="30000"
          closeMethod="close"
          maxActive="10"
          maxIdle="5"
          minIdle="1"
          removeAbandonedTimeout="60"
          removeAbandoned="false"
          logAbandoned="true"
          minEvictableIdleTimeMillis="30000"
          jdbcInterceptors="org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer"
          username="root"
          password="password"
          driverClassName="com.mysql.jdbc.Driver"
          url="jdbc:mysql://aamhszwo5p1rrw.cf7vbk9ataaz.us-west-2.rds.amazonaws.com:3306/broadleaf"/>

</Context>

When I restart my tomcat I receive the following exception.

SEVERE: Unable to create initial connections of pool.
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Too many connections
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
    at com.mysql.jdbc.Util.getInstance(Util.java:381)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:984)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:910)
    at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:3923)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1273)

I am not sure how the connections are getting maxed out without having my webapp fire any query or even connect to database

回答1:

You're facing a quota of allowed connections into your AWS database. By setting up 4 datasources with each 10 connections into that database, you exceed that limit.

By reducing the maxActive to something lower (say... 3?) you should be good to go (for now)

As for performance considerations: This will work fine as long as none of your pools gets too active.

In the long term I'd recommend one or more of those:

• get a larger connections quota on your db in AWS
• get more users with different permissions to reflect your desired usage
• reduce number of pools - if they're on the same db doing similar stuff, you might be better of with one pool with all your quota assigned. So you can assign connections where they're needed most at that time.

来源：https://stackoverflow.com/questions/34328821/too-many-connections-tomcat7-on-aws-ec2