C3P0 apparent deadlock,

C3P0 apparent deadlock,

1. After running c3p0 for a period of time, the following error is reported:

W 07-26_00:58:27 ThreadPoolAsynchronousRunner.java 608 com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@70929ab6 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks! W 07-26_00:58:39 ThreadPoolAsynchronousRunner.java 608 com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@4496b93a -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!

2. solution:

1. Update c3p0 to 0.9.2.1. This version optimizes the connection acquisition rules.

2. First modify the c3p0 configuration parameters

<! -- JDBC standard parameter, used to control the number of PreparedStatements loaded in the data source. However, the pre-cached statements belong to a single connection rather than the entire connection pool. Therefore, you need to consider many factors when setting this parameter. If both maxStatements and maxStatementsPerConnection are 0, the cache is disabled. Default: 0 --> <property name = "maxStatements" value = "0"/> <! -- The time for the customer to wait for the connection to be obtained after calling getConnection () when the connection pool is used up, in milliseconds. --> <! -- SQLEXCEPTION. If it is set to 0, the system waits infinitely. Default: 0 --> <property name = "checkoutTimeout" value = "100"/>