{"action":"created","issue":{"url":"https://api.github.com/repos/apache/spark/issues/12899","repository_url":"https://api.github.com/repos/apache/spark","labels_url":"https://api.github.com/repos/apache/spark/issues/12899/labels{/name}","comments_url":"https://api.github.com/repos/apache/spark/issues/12899/comments","events_url":"https://api.github.com/repos/apache/spark/issues/12899/events","html_url":"https://github.com/apache/spark/pull/12899","id":153035244,"number":12899,"title":"[SPARK-12837][CORE] reduce network IO for accumulators","user":{"login":"cloud-fan","id":3182036,"avatar_url":"https://avatars.githubusercontent.com/u/3182036?v=3","gravatar_id":"","url":"https://api.github.com/users/cloud-fan","html_url":"https://github.com/cloud-fan","followers_url":"https://api.github.com/users/cloud-fan/followers","following_url":"https://api.github.com/users/cloud-fan/following{/other_user}","gists_url":"https://api.github.com/users/cloud-fan/gists{/gist_id}","starred_url":"https://api.github.com/users/cloud-fan/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/cloud-fan/subscriptions","organizations_url":"https://api.github.com/users/cloud-fan/orgs","repos_url":"https://api.github.com/users/cloud-fan/repos","events_url":"https://api.github.com/users/cloud-fan/events{/privacy}","received_events_url":"https://api.github.com/users/cloud-fan/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":16,"created_at":"2016-05-04T15:04:45Z","updated_at":"2016-05-05T09:51:50Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/apache/spark/pulls/12899","html_url":"https://github.com/apache/spark/pull/12899","diff_url":"https://github.com/apache/spark/pull/12899.diff","patch_url":"https://github.com/apache/spark/pull/12899.patch"},"body":"## What changes were proposed in this pull request?\r\n\r\nSending un-updated accumulators back to driver makes no sense, as merging a zero value accumulator is a no-op. We should only send back updated accumulators, to save network IO.\r\n\r\n\r\n## How was this patch tested?\r\n\r\nto do\r\n"},"comment":{"url":"https://api.github.com/repos/apache/spark/issues/comments/217115088","html_url":"https://github.com/apache/spark/pull/12899#issuecomment-217115088","issue_url":"https://api.github.com/repos/apache/spark/issues/12899","id":217115088,"user":{"login":"SparkQA","id":8108735,"avatar_url":"https://avatars.githubusercontent.com/u/8108735?v=3","gravatar_id":"","url":"https://api.github.com/users/SparkQA","html_url":"https://github.com/SparkQA","followers_url":"https://api.github.com/users/SparkQA/followers","following_url":"https://api.github.com/users/SparkQA/following{/other_user}","gists_url":"https://api.github.com/users/SparkQA/gists{/gist_id}","starred_url":"https://api.github.com/users/SparkQA/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/SparkQA/subscriptions","organizations_url":"https://api.github.com/users/SparkQA/orgs","repos_url":"https://api.github.com/users/SparkQA/repos","events_url":"https://api.github.com/users/SparkQA/events{/privacy}","received_events_url":"https://api.github.com/users/SparkQA/received_events","type":"User","site_admin":false},"created_at":"2016-05-05T09:51:50Z","updated_at":"2016-05-05T09:51:50Z","body":"**[Test build #57866 has finished](https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/57866/consoleFull)** for PR 12899 at commit [`c523fee`](https://github.com/apache/spark/commit/c523feeb58376ed4813d1e5119638fe6528f742a).\n * This patch **fails Spark unit tests**.\n * This patch merges cleanly.\n * This patch adds no public classes."}}