{"action":"opened","issue":{"url":"https://api.github.com/repos/intel-hadoop/gearpump/issues/502","labels_url":"https://api.github.com/repos/intel-hadoop/gearpump/issues/502/labels{/name}","comments_url":"https://api.github.com/repos/intel-hadoop/gearpump/issues/502/comments","events_url":"https://api.github.com/repos/intel-hadoop/gearpump/issues/502/events","html_url":"https://github.com/intel-hadoop/gearpump/issues/502","id":57765682,"number":502,"title":"KafkaStorage loading data takes a long time","user":{"login":"manuzhang","id":1191767,"avatar_url":"https://avatars.githubusercontent.com/u/1191767?v=3","gravatar_id":"","url":"https://api.github.com/users/manuzhang","html_url":"https://github.com/manuzhang","followers_url":"https://api.github.com/users/manuzhang/followers","following_url":"https://api.github.com/users/manuzhang/following{/other_user}","gists_url":"https://api.github.com/users/manuzhang/gists{/gist_id}","starred_url":"https://api.github.com/users/manuzhang/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/manuzhang/subscriptions","organizations_url":"https://api.github.com/users/manuzhang/orgs","repos_url":"https://api.github.com/users/manuzhang/repos","events_url":"https://api.github.com/users/manuzhang/events{/privacy}","received_events_url":"https://api.github.com/users/manuzhang/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-02-16T05:09:33Z","updated_at":"2015-02-16T05:09:33Z","closed_at":null,"body":"KafkaStorage uses `immutable.LIst` (which has bad performance) to construct loaded data but `immutable.List`, which takes a long time (not finished for a one-minute job). That will block KafkaSource and KafkaStreamProducer, and thus the whole DAG. "}}