我有许多任务/ servlet正在击中HardDeadlineExceededError，这使得一切都处于“仍在执行”的状态。
正在完成的工作很容易超过29秒的阈值。
我尝试捕获DeadlineExceededException并基于Exception来保存退出 状态，但这些异常处理程序都没有被捕获......
有没有办法确定哪些任务在队列中或当前正在执行？
还有其他策略来处理这种情况吗？
我正在处理的情况记录在"The Request Timer"标题下。
// task handler for retrieving information from external web services
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
String taskRetryCountParam = req.getParameter( "X-AppEngine-TaskRetryCount" );
int taskRetryCount = (taskRetryCountParam==null) ? 0 : Integer.parseInt(taskRetryCountParam);
// look up the persistent 'task' and mark it as 'running'
logger.info( this.getClass().getName() + ".doPost( "+ taskId + " ) retryCount=" + taskRestryCount );
// Do lots of heavy lifting here
// like calling external web services using URL fetch service
// and saving the contents into our database.
// look up the persistent 'task' and mark it as 'completed'
} catch ( DeadlineExceededException deadline ) {
// got this deadline exception
// look up the persistent 'task' and mark it as 'errored - try again'
logger.warning( "DeadlineExceeded Exception while loading content " + deadline.getMessage() );
resp.setStatus( HttpServletResponse.SC_REQUEST_TIMEOUT );
}
} catch ( Exception unknown ) {
// got some unknown exception
// look up the persistent 'task' and mark it as 'errored - cancelled'
logger.severe( "General Exception while loading content exception:" + unknown.getMessage() );
resp.setStatus( HttpServletResponse.SC_OK );
}
}
当我遇到这种情况时，这是日志文件条目......看来我的数据库事务花费的时间太长了。
W 05-30 12:42PM 09.535
Error for /loadstatus
com.google.apphosting.runtime.HardDeadlineExceededError: This request (083793d1091c2ca3) started at 2010/05/30 19:41:39.814 UTC and was still executing at 2010/05/30 19:42:09.529 UTC.
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:443)
at java.util.concurrent.TimeUnit.timedWait(Unknown Source)
at com.google.apphosting.runtime.AsyncFuture.get(AsyncFuture.java:60)
at com.google.apphosting.runtime.ApiProxyImpl$AsyncApiFuture.get(ApiProxyImpl.java:326)
at com.google.apphosting.runtime.ApiProxyImpl$AsyncApiFuture.get(ApiProxyImpl.java:217)
at com.google.apphosting.runtime.ApiProxyImpl.doSyncCall(ApiProxyImpl.java:131)
at com.google.apphosting.runtime.ApiProxyImpl.access$000(ApiProxyImpl.java:43)
at com.google.apphosting.runtime.ApiProxyImpl$1.run(ApiProxyImpl.java:104)
at com.google.apphosting.runtime.ApiProxyImpl$1.run(ApiProxyImpl.java:102)
at java.security.AccessController.doPrivileged(Native Method)
at com.google.apphosting.runtime.ApiProxyImpl.makeSyncCall(ApiProxyImpl.java:102)
at com.google.apphosting.runtime.ApiProxyImpl.makeSyncCall(ApiProxyImpl.java:43)
at com.google.apphosting.api.ApiProxy.makeSyncCall(ApiProxy.java:98)
at com.google.appengine.api.datastore.DatastoreApiHelper.makeSyncCall(DatastoreApiHelper.java:58)
at com.google.appengine.api.datastore.TransactionImpl.makeSyncCall(TransactionImpl.java:42)
at com.google.appengine.api.datastore.TransactionImpl.makeSyncCall(TransactionImpl.java:56)
at com.google.appengine.api.datastore.TransactionImpl.commit(TransactionImpl.java:66)
at org.datanucleus.store.appengine.DatastoreTransaction.commit(DatastoreTransaction.java:61)
at org.datanucleus.store.appengine.DatastoreXAResource.commit(DatastoreXAResource.java:88)
at org.datanucleus.transaction.Transaction.commit(Transaction.java:149)
at org.datanucleus.transaction.TransactionManager.commit(TransactionManager.java:95)
at org.datanucleus.TransactionImpl.internalCommit(TransactionImpl.java:390)
at org.datanucleus.TransactionImpl.commit(TransactionImpl.java:258)
at org.datanucleus.jdo.JDOTransaction.commit(JDOTransaction.java:83)
at org.datanucleus.store.appengine.jdo.DatastoreJDOTransaction.commit(DatastoreJDOTransaction.java:56)
<snip>
C 05-30 12:42PM 09.629
Uncaught exception from servlet
com.google.apphosting.runtime.HardDeadlineExceededError: This request (083793d1091c2ca3) started at 2010/05/30 19:41:39.814 UTC and was still executing at 2010/05/30 19:42:09.529 UTC.
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:443)
at java.util.concurrent.TimeUnit.timedWait(Unknown Source)
at com.google.apphosting.runtime.AsyncFuture.get(AsyncFuture.java:60)
at com.google.apphosting.runtime.ApiProxyImpl$AsyncApiFuture.get(ApiProxyImpl.java:326)
at com.google.apphosting.runtime.ApiProxyImpl$AsyncApiFuture.get(ApiProxyImpl.java:217)
at com.google.apphosting.runtime.ApiProxyImpl.doSyncCall(ApiProxyImpl.java:131)
at com.google.apphosting.runtime.ApiProxyImpl.access$000(ApiProxyImpl.java:43)
at com.google.apphosting.runtime.ApiProxyImpl$1.run(ApiProxyImpl.java:104)
at com.google.apphosting.runtime.ApiProxyImpl$1.run(ApiProxyImpl.java:102)
at java.security.AccessController.doPrivileged(Native Method)
at com.google.apphosting.runtime.ApiProxyImpl.makeSyncCall(ApiProxyImpl.java:102)
at com.google.apphosting.runtime.ApiProxyImpl.makeSyncCall(ApiProxyImpl.java:43)
at com.google.apphosting.api.ApiProxy.makeSyncCall(ApiProxy.java:98)
at com.google.appengine.api.datastore.DatastoreApiHelper.makeSyncCall(DatastoreApiHelper.java:58)
at com.google.appengine.api.datastore.TransactionImpl.makeSyncCall(TransactionImpl.java:42)
at com.google.appengine.api.datastore.TransactionImpl.makeSyncCall(TransactionImpl.java:56)
at com.google.appengine.api.datastore.TransactionImpl.commit(TransactionImpl.java:66)
at org.datanucleus.store.appengine.DatastoreTransaction.commit(DatastoreTransaction.java:61)
at org.datanucleus.store.appengine.DatastoreXAResource.commit(DatastoreXAResource.java:88)
at org.datanucleus.transaction.Transaction.commit(Transaction.java:149)
at org.datanucleus.transaction.TransactionManager.commit(TransactionManager.java:95)
at org.datanucleus.TransactionImpl.internalCommit(TransactionImpl.java:390)
at org.datanucleus.TransactionImpl.commit(TransactionImpl.java:258)
at org.datanucleus.jdo.JDOTransaction.commit(JDOTransaction.java:83)
at org.datanucleus.store.appengine.jdo.DatastoreJDOTransaction.commit(DatastoreJDOTransaction.java:56)
<snip>
W 05-30 12:42PM 09.644
A serious problem was encountered with the process that handled this request, causing it to exit. This is likely to cause a new process to be used for the next request to your application. If you see this message frequently, you may be throwing exceptions during the initialization of your application. (Error code 104)
答案 0 :(得分：3)
http://groups.google.com/group/google-appengine-java/msg/e3fd2b621bb96013
如果在您自己的代码中发生HDEE，则可以在没有DEE的情况下抛出HDEE 通常，最耗时的事情是等待API调用 返回所以这里的超时将导致API调用停止与 DEE。因此，如果您不经常调用API，则可以直接访问HDEE。
我还有长时间运行的任务，它们遍历数据处理 并存储结果。我使用一个停止返回结果的迭代器 20秒后，保存最后一个处理过的对象，然后踢出 关闭一项新任务继续处理。
我原来的解决方案抓住了DEE然后清理了但是这个 停止了可靠的工作。