只要应用程序从有限的几个永久进程中创建和关闭连接，连接池就可以改善性能。
If the application creates and drops connections from a limited number of persistent processes, the connection pooling will certainly improve the performance.
性能测试是确定应用程序在各种负载情景中的(JVM、连接池等)最佳设置的唯一方式。
Performance testing is the only way to determine the optimal Settings (for JVM, connection pooling, etc.) for an application in a variety of load scenarios.
根据规范，应用程序模块使用数据库连接池需要两个步骤。
As per the specification, two steps are needed for an application module to use a database connection pool.
通常，这对于在应用服务器上运行的应用程序是不可能的，因为这些应用程序使用连接池，连接不是个人化的。
Generally, it is not possible for applications running on an application server because these applications use connection pooling so that connections are not personalized.
为连接池大小配置适当的值是一个应用程序服务器调优问题。
Configuring proper values for connection pool sizes is a matter of tuning an application server.
此外，现在您可以获得连接池其他应用程序服务器提供商的功能性好处。
Moreover, now you can get the benefits of connection pooling and other application server-provided functionality.
打开和关闭连接的过程开销较大，会影响到应用程序或数据库的性能，而使用连接池就可以消除大部分这样的开销。
Opening and closing connections is an expensive process affecting application or database performance and the use of connection pooling helps eliminate most of that overhead.
这使得资源适配器及应用程序服务器共享资源并提供例如安全、连接池及事务处理这样的服务。
This allows the resource adapter and application server to share resources and provide services such as security, connection pooling, and transaction management.
清单4显示了在应用程序模块中查找创建的数据库连接池所需的代码。
Listing 4 shows the code in the application module needed to lookup the created database connection pool.
大多数业务程序员都不愿意，为了使用JDBCSPI而编写他们自己的数据源和连接池代码，并实现一个命名的服务器。
Most business programmers cannot justify the time it takes to write their own datasource and connection pool code plus implement a naming server so the JDBC SPI can be used.
按照J2EE标准中的定义，应用程序服务器可以提供连接池机制，从而无需为每个传入请求重新创建连接。
As defined in the J2EE standard, application servers can provide a pooling facility so the connections do not need to be recreated with every incoming request.
对于典型的J2EE应用程序，会对所有数据库访问使用单个连接池标识。
With typical J2EE applications, a single connection pool identity is used for all database access.
在受管模式下，应用程序服务器与资源适配器建立接口，从而管理诸如连接池、事务管理、跟踪和安全性之类的服务质量特性。
Under managed mode, the application server interfaces with resource adapters to manage quality of service features such as connection pooling, transaction management, tracing, and security.
比如数据库连接池就是单例设计模式的一个例子：我们一般不想让应用程序具有连接池类的多个资源密集型实例。
An example use case for a singleton would be a database connection pool: you don't want your application to have multiple resource-intensive instances of a connection pool class.
值得一提的是，每个MQ消息传递提供程序连接工厂都有单一的连接池，池中的每个连接都有自已的会话池。
It is worth noting that there is a single connection pool per MQ messaging provider connection factory, and each connection in the pool has its own session pool.
这类应用程序就无法使用ODBC管理器所提供的简单连接池的好处。
This type of application will not benefit from the simple connection pooling provided by the ODBC manager.
通常而言，许多应用程序都可以通过调优以下三个核心区域实现一定程度的性能改进：J VM、线程池和连接池。
In general, a large number of applications will realize some improvement from tuning in three core areas: the JVM, thread pools, and connection pools.
另外，这些属性还允许管理员很好地优化连接池，从而使应用程序的性能特点发挥到极致。
Additionally, the properties allow administrators to fine tune the connection pool to maximize performance characteristics of the application.
这使托管连接可以返回连接池，为应用程序的其他部分所使用。
This lets the managed connection be returned to the pool for use by other parts of the application.
同样地，应用程序设计也能调优性能：更少的对象创建、实时的数据库优化以及使用数据库连接池。
Similarly the application design can be tuned for performance: Fewer object creations, ongoing database refinements, and using database connection pooling.
现在，应用程序可以获得连接池。
任何仍在使用连接管理器api的应用程序必须转而使用JDBC 2.0连接池。
Any applications that are still using the connection manager APIs must be changed to use JDBC 2.0 connection pooling.
连接池最长等待时间：显示应用程序阻塞，等待连接池连接的最长时间。
Maximum connection wait time - Shows the maximum time that an application was blocked waiting for a connection from the pool.
使用有连接池的JDBC资源的应用程序需要设置连接池的大小。
Applications that make use of connection pooled JDBC resources need to set the size of the connection pool.
应用程序等待的时间是在连接池的连接超时属性中指定的，缺省值为 180秒（3分钟）。
The time the application waits is specified in the Connection Pool's Connection timeout property, which has a default value of 180 seconds (3 minutes).
如果应用程序有高并发，而最大池大小又太小，连接池就会经常等待。
If your application has high concurrency and your maximum pool size is too small, your connection pool will often experience waiting.
总的来说，连接池是一个到JMS提供程序的空闲连接池。
In general terms, a connection pool is a pool of free connections to a JMS provider.
连接池将连接开销分散分布在若干用户请求中，以便保留应用程序资源供未来请求使用。
Connection pooling spreads the connection overhead across several user requests, thereby conserving application resources for future requests.
链中的最后一个“门”是应用程序访问的数据源的连接池的大小。
The final gate in the chain is the size of the connection pool to the data sources accessed by the application.
因此，应用程序采用连接池机制至关重要。
Therefore, it is very important that an application employs a connection pooling mechanism.
应用推荐