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POTomcat and mySQL configurations
 

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  1. POTomcat and mySQL configurations
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    <p>I have been using Tomcat and mySQL for quite awhile but recently have been managing to max out my connections. I don't know why as my code opens and closes the connection when its done. For instance here is my connect and close methods:</p> <pre><code>public void closeConnection(){ try { con.close(); } catch (SQLException e) { e.printStackTrace(); } } public void connect(){ try { initCtx = new InitialContext(); } catch (NamingException e) { e.printStackTrace(); } try { envCtx = (Context) initCtx.lookup("java:comp/env"); } catch (NamingException e) { e.printStackTrace(); } try { ds = (DataSource) envCtx.lookup("jdbc/TestDB"); } catch (NamingException e) { e.printStackTrace(); } } </code></pre> <p>And this is a basic method to execute a generic statement:</p> <pre><code>public void excuteStatement(String query){ connect(); try { con = ds.getConnection(); con.createStatement().executeUpdate(query); } catch (Exception ex ){ } finally { if (con != null) closeConnection(); } } </code></pre> <p>Is there any reason this sort of code should cause a connection to be left open? I get all the data I need, everything works fine 99% of the time. </p> <p>This is my configuration in the Tomcat context.xml:</p> <pre><code> &lt;Resource name="jdbc/TestDB" auth="Container" type="javax.sql.DataSource" maxActive="100" maxIdle="30" maxWait="10000" username="myUserName" password="myPass" driverClassName="com.mysql.jdbc.Driver" url="jdbc:mysql://xxx.xxx.xxx.xxx:0000/myUserName"/&gt; </code></pre> <p>Now at this very moment I'm locked out as I have max connections. Should I lower the wait time to avoid this? </p> <p>One thing I should say about my code, its often that it will trigger many multiple statements in large loops. I think perhaps this rapid opening and closing could be the issue. As my Tomcat servlet is always running should it just open a connection once and leave it open with checks to make sure its still active rather than always opening a connection and closing it? </p> <p>Thanks for any and all advice on this. </p>
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    1. USJames Elegan
    1. USJames MV
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    1. COWRT your question- when your connections max out does your app hang? If so you might be having problems with a combination of synchronization locks in your code and table locks
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      1. USMartin Wilson
    2. COWhat's the actual problem you are seeing? It looks like you're using a connection pool so your connections won't really be being closed, just put back in the pool. This might explain why your connections are being left open!
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      1. USMartin Wilson
    3. COHow should I use a connection pool? The problem is the database maxes out connections. The app doesnt hang it just cant get any data.
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      1. USJames MV
 

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