[ http://issues.apache.org/jira/browse/NUTCH-152?page=comments#action_12362043 ]
Paul Baclace commented on NUTCH-152: ------------------------------------ >re 3: Why is a separate thread needed for stdout? It certainly makes the code easier to read. Using the main thread to read the subprocess stdout is a clever deviation from the usual idiom of using a separate thread. Programming defensively, being able to setDaemon(true) and interrupt() a separate thread eliminates any possibility that external, unexpected problems (bugs) will not cause a hang or resource leak. >re 4: I'd expect the io pipes to get EOF when the process is killed. If the subprocess is hanging in a device driver, it might not be killed in a timely fashion, so the EOF might not arrive immediately. Rare, but not impossible. > TaskRunner io pipes are not setDaemon(true), cleanup and exception errors are > incomplete, max heap too small > ------------------------------------------------------------------------------------------------------------ > > Key: NUTCH-152 > URL: http://issues.apache.org/jira/browse/NUTCH-152 > Project: Nutch > Type: Bug > Components: fetcher > Versions: 0.8-dev > Environment: all > Reporter: Paul Baclace > Attachments: TaskRunner.java.patch > > 1. io pipes should be setDaemon(true) so that process cannot hang. > 2. error messages for Exceptions are incomplete since e.getMessage() is used > and it can be empty (NullPointerException has an empty message). Change > this to e.toString() which always has more meaning. > 3. a separate thread is not used for the subprocess stdout pipe, but it must > be a separate thread if setDaemon(true). > 4. TaskRunner.kill() does not stop the io pipe threads, but it should. > 5. If InterruptedException occurs, it was assumed to be for the current > (main) thread, but it should check this with Thread.interrupted() otherwise > spurious thread interrupts will be rethrown as IOException. > 6. A recent run had some Tasktracker child processes that ran out of heap. > The default max heap size should be larger. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
