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https://issues.apache.org/jira/browse/HIVE-20250?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16565715#comment-16565715
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Jason Dere commented on HIVE-20250:
-----------------------------------
Had some offline discussion with [~hagleitn] on this and there is concern that
users might too easily enable
hive.query.results.cache.external.tables.enabled/hive.query.results.cache.nontransactional.tables.enabled
without considering the ramifications - that Hive will continue to serve stale
cached results if such tables are modified outside of Hive.
One option we have talked about is replacing
hive.query.results.cache.max.entry.lifetime with a new timeout setting that
only applies to non-transactional/external tables, as both [~gopalv] and
[~hagleitn] have argued that cached results from transactional tables do not
need to be timed out (there is other logic to automatically invalidate results
on transactional tables if a transactional table has been updated using a
transaction). So
hive.query.results.cache.external.tables.enabled/hive.query.results.cache.nontransactional.tables.enabled/hive.query.results.cache.max.entry.lifetime
would be replaced by some new setting like
hive.query.results.cache.nontransactional.result.lifetime (defaulted to 0),
where setting this value with a positive value would enable results caching for
non-transactional tables, where the cached result would be considered valid for
as long as the value of that setting.
> Option to allow external tables to use query results cache
> ----------------------------------------------------------
>
> Key: HIVE-20250
> URL: https://issues.apache.org/jira/browse/HIVE-20250
> Project: Hive
> Issue Type: Sub-task
> Reporter: Jason Dere
> Priority: Major
> Attachments: HIVE-20250.1.patch
>
>
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