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https://issues.apache.org/jira/browse/HIVE-13884?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15342416#comment-15342416
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Sergio Peña commented on HIVE-13884:
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Thanks [~sershe].
[~mohitsabharwal] [~brocknoland] I run a test with 10K partitions {{select *
from table12 where dt < 10000}} with the variable enabled and disabled. There's
not too much difference. I got a difference of 1 second, and I tested it 5
times each time, even without the patch applied. I think we are good to go for
this.
I'll wait until HIVE-14055 is fixed as I would need to change this patch as
well.
> Disallow queries fetching more than a configured number of partitions in
> PartitionPruner
> ----------------------------------------------------------------------------------------
>
> Key: HIVE-13884
> URL: https://issues.apache.org/jira/browse/HIVE-13884
> Project: Hive
> Issue Type: Improvement
> Reporter: Mohit Sabharwal
> Assignee: Sergio Peña
> Attachments: HIVE-13884.1.patch, HIVE-13884.2.patch,
> HIVE-13884.3.patch, HIVE-13884.4.patch, HIVE-13884.5.patch, HIVE-13884.6.patch
>
>
> Currently the PartitionPruner requests either all partitions or partitions
> based on filter expression. In either scenarios, if the number of partitions
> accessed is large there can be significant memory pressure at the HMS server
> end.
> We already have a config {{hive.limit.query.max.table.partition}} that
> enforces limits on number of partitions that may be scanned per operator. But
> this check happens after the PartitionPruner has already fetched all
> partitions.
> We should add an option at PartitionPruner level to disallow queries that
> attempt to access number of partitions beyond a configurable limit.
> Note that {{hive.mapred.mode=strict}} disallow queries without a partition
> filter in PartitionPruner, but this check accepts any query with a pruning
> condition, even if partitions fetched are large. In multi-tenant
> environments, admins could use more control w.r.t. number of partitions
> allowed based on HMS memory capacity.
> One option is to have PartitionPruner first fetch the partition names
> (instead of partition specs) and throw an exception if number of partitions
> exceeds the configured value. Otherwise, fetch the partition specs.
> Looks like the existing {{listPartitionNames}} call could be used if extended
> to take partition filter expressions like {{getPartitionsByExpr}} call does.
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