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https://issues.apache.org/jira/browse/HIVE-14199?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15431994#comment-15431994
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Saket Saurabh commented on HIVE-14199:
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Thanks [~ekoifman] for reviewing it.
> Enable Bucket Pruning for ACID tables
> -------------------------------------
>
> Key: HIVE-14199
> URL: https://issues.apache.org/jira/browse/HIVE-14199
> Project: Hive
> Issue Type: Improvement
> Components: Transactions
> Reporter: Saket Saurabh
> Assignee: Saket Saurabh
> Fix For: 2.2.0
>
> Attachments: HIVE-14199.01.patch, HIVE-14199.02.patch,
> HIVE-14199.03.patch
>
>
> Currently, ACID tables do not benefit from the bucket pruning feature
> introduced in HIVE-11525. The reason for this has been the fact that bucket
> pruning happens at split generation level and for ACID, traditionally the
> delta files were never split. The parallelism for ACID was then restricted to
> the number of buckets. There would be as many splits as the number of buckets
> and each worker processing one split would inevitably read all the delta
> files for that bucket, even when the query may have originally required only
> one of the buckets to be read.
> However, HIVE-14035 now enables even the delta files to be also split. What
> this means is that now we have enough information at the split generation
> level to determine appropriate buckets to process for the delta files. This
> can efficiently allow us to prune unnecessary buckets for delta files and
> will lead to good performance gain for a large number of selective queries on
> ACID tables.
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