WARNING: Failed to execute: select * from cl_service_set because: Communications link failure The last packet successfully received from the server was 345,489 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago. 2015-11-11 18:02:06,233 [http-bio-8080-exec-5] ERROR errors.GrailsExceptionResolver - MySQLNonTransientConnectionException occurred when processing request: [GET] /Xxxxx/xxxx/xxxx Communications link failure during commit(). Transaction resolution unknown.. Stacktrace follows: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Communications link failure during commit(). Transaction resolution unknown. at com.mysql.jdbc.Util.handleNewInstance(Util.java:404) at com.mysql.jdbc.Util.getInstance(Util.java:387) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:919) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:898) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:887) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:862) at com.mysql.jdbc.ConnectionImpl.commit(ConnectionImpl.java:1621) at grails.plugin.cache.web.filter.PageFragmentCachingFilter.doFilter(PageFragmentCachingFilter.java:198) at grails.plugin.cache.web.filter.AbstractFilter.doFilter(AbstractFilter.java:63) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1146) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:701)
解决办法参考:
http://stackoverflow.com/questions/12532003/how-do-i-configure-c3p0-for-a-grails-2-x-application-with-multiple-datasources
http://stackoverflow.com/questions/3404255/configuring-grails-to-use-own-datasource-implementation-or-to-proxy-the-standard
http://stackoverflow.com/questions/11125962/correct-way-to-keep-pooled-connections-alive-or-time-them-out-and-get-fresh-one