JBoss NestedSQLException No ManagedConnections

org.jboss.util.NestedSQLException: No ManagedConnections


Pooling parameters

* - whether separate subpools should be created for connections inside and outside JTA transactions (default false)
* - the minimum number of connections in the pool (default 0 - zero)
* - the maximum number of connections in the pool (default 20)
* - the length of time to wait for a connection to become available when all the connections are checked out (default 5000 == 5 seconds, from 3.2.4 it is 30000 == 30 seconds)
* - the number of minutes after which unused connections are closed (default 15 minutes)
* - whether the connection should be "locked" to the transaction, returning it to the pool at the end of the transaction (default true for Local, false for XA)

A.2.6. Too many connections

If you get a Too many connections error when you try to connect to the mysqld server, this means that all available connections are in use by other clients.

The number of connections allowed is controlled by the max_connections system variable. Its default value is 100. If you need to support more connections, you should restart mysqld with a larger value for this variable.

mysqld actually allows max_connections+1 clients to connect. The extra connection is reserved for use by accounts that have the SUPER privilege. By granting the SUPER privilege to administrators and not to normal users (who should not need it), an administrator can connect to the server and use SHOW PROCESSLIST to diagnose problems even if the maximum number of unprivileged clients are connected. See Section, “SHOW PROCESSLIST Syntax”.

The maximum number of connections MySQL can support depends on the quality of the thread library on a given platform. Linux or Solaris should be able to support 500-1000 simultaneous connections, depending on how much RAM you have and what your clients are doing. Static Linux binaries provided by MySQL AB can support up to 4000 connections.

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