[
https://issues.apache.org/jira/browse/IMPALA-10147?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Riza Suminto reassigned IMPALA-10147:
-------------------------------------
Assignee: Riza Suminto
> Avoid getting a file handle for data cache hits
> -----------------------------------------------
>
> Key: IMPALA-10147
> URL: https://issues.apache.org/jira/browse/IMPALA-10147
> Project: IMPALA
> Issue Type: Improvement
> Components: Backend
> Affects Versions: Impala 4.0
> Reporter: Joe McDonnell
> Assignee: Riza Suminto
> Priority: Critical
>
> When reading from the data cache, the DiskIo thread first gets a file handle,
> then it checks the data cache for a hit. If there is a cache hit, then the
> file handle is not actually used. It is only used if there is a cache miss.
> There is no real reason to have the file handle open for cache hits. It
> doesn't really serve any additional purpose, and it adds overhead to cache
> hits.
> For platforms that do not have the file handle cache, this can be a
> significant overhead.
> We should only open the file handle after we have checked the data cache and
> know that we need to read from regular storage.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
