alirezazamani commented on a change in pull request #741: Fix ConcurrentModification exception in Workflow Garbage Collection URL: https://github.com/apache/helix/pull/741#discussion_r383097458
########## File path: helix-core/src/main/java/org/apache/helix/task/TaskUtil.java ########## @@ -1043,23 +1043,40 @@ public static void purgeExpiredJobs(String workflow, WorkflowConfig workflowConf * @param dataProvider * @param manager */ - public static void workflowGarbageCollection(WorkflowControllerDataProvider dataProvider, + public static void workflowGarbageCollection(final WorkflowControllerDataProvider dataProvider, final HelixManager manager) { // Garbage collections for conditions where workflow context exists but config is missing. - Map<String, ZNRecord> contexts = dataProvider.getContexts(); - HelixDataAccessor accessor = manager.getHelixDataAccessor(); - HelixPropertyStore<ZNRecord> propertyStore = manager.getHelixPropertyStore(); + Set<String> existingContexts; + /* + * Here try-catch is used to avoid concurrent modification exception while doing deep copy. + * Map.keySet() can produce concurrent modification exception. + * Reason: If the map is modified while an iteration over the set is in progress, concurrent + * modification exception will be thrown. + */ + try { + existingContexts = new HashSet<>(dataProvider.getContexts().keySet()); Review comment: dataProvider.getContexts() is outside the scope of this class and perhaps there are performance concerns regarding this. Maybe we can consider this in next design of TF. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@helix.apache.org For additional commands, e-mail: reviews-h...@helix.apache.org