hive-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Gopal V (JIRA)" <>
Subject [jira] [Commented] (HIVE-13920) LLAP: pre-populate CVB cache
Date Thu, 02 Jun 2016 06:21:59 GMT


Gopal V commented on HIVE-13920:

Preallocating might actually allocate large number of arrays without actual need - a 10,000
row split shouldn't need 128 vector batches pre-created and adding to the garbage.

The allocation is currently inside the actual reader inner loop, which is a problem because
for the first 128 invocations (& more), the allocation is actually performed.

The 128x more allocations than the regular Tez codepath is the problem, moving it around to
a different part of code doesn't fix the actual perf issue.

> LLAP: pre-populate CVB cache
> ----------------------------
>                 Key: HIVE-13920
>                 URL:
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Sergey Shelukhin
> To avoid allocations on the main path, we should pre-populate the CVB cache. The main
difficulty is propagating column indexes earlier to allocate correct vectors.

This message was sent by Atlassian JIRA

View raw message