dbcp配置选项

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testOnBorrow默认为true, 要设置为false. ?若设置validationQuery则对性能影响比较大.

testWhileIdle默认为false,设置为true.并设置validationQuery

maxIdle最好设置为与maxActive一样。

initialSize与minIdle按业务要求配置，一般都要配置。

timeBetweenEvictionRunsMillis默认为-1.设置一定数值300000

numTestsPerEvictionRun默认是3, 这个值要调大点maxActive的一半较好。?

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以下apache dbcp的配置项

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ParametersNOTE: If maxIdle is set too low on heavily loaded systems it is possible you will see connections being closed and almost immediately new connections being opened. This is a result of the active threads momentarily closing connections faster than they are opening them, causing the number of idle connections to rise above maxIdle. The best value for maxIdle for heavily loaded system will vary but the default is a good starting point.

NOTE: Versions 1.3 and 1.4 of DBCP incorrectly use "initConnectionSqls" as the name of this property for JNDI object factory configuration. Until 1.3.1/1.4.1 are released, "initConnectionSqls" must be used as the name for this property when using BasicDataSoureFactory to create BasicDataSource instances via JNDI.nullA Collection of SQL statements that will be used to initialize physical connections when they are first created. These statements are executed only once - when the configured connection factory creates the connection.?This component has also the ability to pool PreparedStatements. When enabled a statement pool will be created for each Connection and PreparedStatements created by one of the following methods will be pooled:

public PreparedStatement prepareStatement(String sql)public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency)

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NOTE?- Make sure your connection has some resources left for the other statements. Pooling PreparedStatements may keep their cursors open in the database, causing a connection to run out of cursors, especially if maxOpenPreparedStatements is left at the default (unlimited) and an application opens a large number of different PreparedStatements per connection. To avoid this problem, maxOpenPreparedStatements should be set to a value less than the maximum number of cursors that can be open on a Connection.

    Connection conn = ds.getConnection();    Connection dconn = ((DelegatingConnection) conn).getInnermostDelegate();    ...    conn.close()

?Default is false, it is a potential dangerous operation and misbehaving programs can do harmfull things. (closing the underlying or continue using it when the guarded connection is already closed) Be carefull and only use when you need direct access to driver specific extentions.

NOTE:?Do not close the underlying connection, only the original one.

?If you have enabled "removeAbandoned" then it is possible that a connection is reclaimed by the pool because it is considered to be abandoned. This mechanism is triggered when (getNumIdle() < 2) and (getNumActive() > getMaxActive() - 3)

?For example maxActive=20 and 18 active connections and 1 idle connection would trigger the "removeAbandoned". But only the active connections that aren't used for more then "removeAbandonedTimeout" seconds are removed, default (300 sec). Traversing a resultset doesn't count as being used.

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