Github user Ben-Zvi commented on a diff in the pull request: https://github.com/apache/drill/pull/938#discussion_r140062933 --- Diff: common/src/main/java/org/apache/drill/common/exceptions/UserException.java --- @@ -536,6 +542,33 @@ public Builder pushContext(final String name, final double value) { * @return user exception */ public UserException build(final Logger logger) { + + // To allow for debugging: + // A spinner code to make the execution stop here while the file '/tmp/drillspin' exists + // Can be used to attach a debugger, use jstack, etc + // The processID of the spinning thread should be in a file like /tmp/spin4148663301172491613.tmp + // along with the error message. + File spinFile = new File("/tmp/drillspin"); + if ( spinFile.exists() ) { + File tmpDir = new File("/tmp"); + File outErr = null; + try { + outErr = File.createTempFile("spin", ".tmp", tmpDir); + BufferedWriter bw = new BufferedWriter(new FileWriter(outErr)); + bw.write("Spinning process: " + ManagementFactory.getRuntimeMXBean().getName() + /* After upgrading to JDK 9 - replace with: ProcessHandle.current().getPid() */); + bw.write("\nError cause: " + + (errorType == DrillPBError.ErrorType.SYSTEM ? ("SYSTEM ERROR: " + ErrorHelper.getRootMessage(cause)) : message)); + bw.close(); + } catch (Exception ex) { + logger.warn("Failed creating a spinner tmp message file: {}", ex); + } + while (spinFile.exists()) { + try { sleep(1_000); } catch (Exception ex) { /* ignore interruptions */ } --- End diff -- Does query killing cause a user exception ?
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