You are viewing a plain text version of this content. The canonical link for it is here.

Posted to issues@impala.apache.org by "Tim Armstrong (JIRA)" <ji...@apache.org> on 2017/07/07 22:32:00 UTC

[jira] [Created] (IMPALA-5629) list::size() in BufferedTupleStreamV2::AdvanceWritePage() is expensive

Tim Armstrong created IMPALA-5629:
-------------------------------------

             Summary: list::size() in BufferedTupleStreamV2::AdvanceWritePage() is expensive
                 Key: IMPALA-5629
                 URL: https://issues.apache.org/jira/browse/IMPALA-5629
             Project: IMPALA
          Issue Type: Sub-task
          Components: Backend
    Affects Versions: Impala 2.10.0
            Reporter: Tim Armstrong
            Assignee: Tim Armstrong


In a test run executing a very large join I saw a lot of CPU being burnt in BufferedTupleStreamV2::AdvanceWritePage() 

It looks like it's all being spent iterating over the pages_ linked list. list::size() is an O(n) operation in some implementations.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)