[GitHub] [rocketmq-externals] imaffe opened a new issue #558: [rocketmq-connect-jdbc: JdbcSinkConnector fetch topic list error]

[GitBox <gi...@apache.org>]

imaffe opened a new issue #558: [rocketmq-connect-jdbc: JdbcSinkConnector fetch topic list error]
URL: https://github.com/apache/rocketmq-externals/issues/558
 
 
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   **BUG REPORT**
   
   1. Please describe the issue you observed:
   According to ISSUE #549 and thanks to @gripson findings, we found that `fetch topic list error` appears at a constant speed even after the connector "semantically" stopped.
   
   The root cause for this is that, runtime doesn't force connectors to stop. It all relies on the connectors `stop()` method to make sure resources are released properly. However because JdbcSinkConnector introduced a route topic listener to monitor route changes, the scheduled task is not cancelled at `stop()`
   
   ```
       public void startListener() {
           listenerHandle = executor.scheduleAtFixedRate(new Runnable() {
               boolean first = true;
               HashMap<String, Set<TaskTopicInfo>> origin = null;
   
               @Override
               public void run() {
                   buildRoute();
                   if (first) {
                       origin = CloneUtils.clone(topicRouteMap);
                       first = false;
                   }
                   if (!compare(origin, topicRouteMap)) {
                       context.requestTaskReconfiguration();
                       origin = CloneUtils.clone(topicRouteMap);
                   }
               }
           }, ((SinkDbConnectorConfig) dbConnectorConfig).getRefreshInterval(), ((SinkDbConnectorConfig) dbConnectorConfig).getRefreshInterval(), TimeUnit.SECONDS);
       }
   ```
   
   A direct solution (but very likely not the best) would be cancel the schedule at `stop()`, something like 
   ```
   listenerHandle.cancel(true);
   ```
   where listenerHandle is a `ScheduledFuture`.
   
   Other solutions are more than welcomed (as I really think mine is so ugly LOL)
   

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