[
https://issues.apache.org/jira/browse/HIVE-15390?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15785716#comment-15785716
]
Thejas M Nair commented on HIVE-15390:
--------------------------------------
cc [~prasanth_j] [~rajesh.balamohan] [~gopalv]
> Orc reader unnecessarily reading stripe footers with
> hive.optimize.index.filter set to true
> -------------------------------------------------------------------------------------------
>
> Key: HIVE-15390
> URL: https://issues.apache.org/jira/browse/HIVE-15390
> Project: Hive
> Issue Type: Bug
> Components: ORC
> Affects Versions: 1.2.1
> Reporter: Abhishek Somani
> Assignee: Abhishek Somani
> Attachments: HIVE-15390.1.patch, HIVE-15390.patch
>
>
> In a split given to a task, the task's orc reader is unnecessarily reading
> stripe footers for stripes that are not its responsibility to read. This is
> happening with hive.optimize.index.filter set to true.
> Assuming one split per task(no tez grouping considered), a task should not
> need to read beyond the split's end offset. Even in some split computation
> strategies where a split's end offset can be in the middle of a stripe, it
> should not need to read more than one stripe beyond the split's end offset(to
> fully read a stripe that started in it). However I see that some tasks make
> unnecessary filesystem calls to read all the stripe footers in a file from
> the split start offset till the end of the file.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
