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

Posted to issues-all@impala.apache.org by "Tim Armstrong (JIRA)" <ji...@apache.org> on 2018/09/27 00:32:00 UTC

[jira] [Created] (IMPALA-7637) Include more hash table stats in profile

Tim Armstrong created IMPALA-7637:
-------------------------------------

             Summary: Include more hash table stats in profile
                 Key: IMPALA-7637
                 URL: https://issues.apache.org/jira/browse/IMPALA-7637
             Project: IMPALA
          Issue Type: Improvement
          Components: Backend
            Reporter: Tim Armstrong


Our hash table collects some useful stats about collisions and travel length, but then we don't do anything to expose them: https://github.com/apache/impala/blob/540611e863fe99b3d3ae35f8b94a745a68b9eba2/be/src/exec/hash-table.h#L989

We should add some of them to the profile, maybe:
* the number of probes
* the average travel length per probe
* the number of hash collisions
* (optional) the number of hash table resizes. We already have the hash table size and the resize time, which I think is sufficient to debug most problems with resizes.




--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-all-unsubscribe@impala.apache.org
For additional commands, e-mail: issues-all-help@impala.apache.org