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 "shajini thayasingh (Jira)" <ji...@apache.org> on 2023/10/11 16:30:00 UTC
[jira] [Commented] (IMPALA-12491) Document whether the remote data cache has TTL
[ https://issues.apache.org/jira/browse/IMPALA-12491?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17774134#comment-17774134 ]
shajini thayasingh commented on IMPALA-12491:
---------------------------------------------
[~stigahuang] I have two questions before I start including about this TTL.
1. Is TTL configurable?
2. How long is the cache? In other words is there a default time for this TTL?
3. So lets say if i use the same metadata in a query but if the ttl time has passed will the scan request still reach the cache?
cc: [~joemcdonnell]
> Document whether the remote data cache has TTL
> ----------------------------------------------
>
> Key: IMPALA-12491
> URL: https://issues.apache.org/jira/browse/IMPALA-12491
> Project: IMPALA
> Issue Type: Documentation
> Reporter: Quanlong Huang
> Priority: Major
> Attachments: impala_data_cache.png
>
>
> It's unclear to the users whether the remote data cache has TTL so will expire after some time. We have document about the startup flags of remote data cache, including the capacity and the eviction policy:
> [https://impala.apache.org/docs/build/html/topics/impala_data_cache.html]
> We should also mention that the cache item won't expire as long as the same file metadata is used in the query. The reason is that the cache key is (filename, mtime, file offset) where mtime is the last modified time of the file. When the mtime in the file metadata doesn't change, the scan request could always hit the cache (if capacity is enough).
> CC [~shajini], [~joemcdonnell]
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-all-unsubscribe@impala.apache.org
For additional commands, e-mail: issues-all-help@impala.apache.org