[jira] [Commented] (HIVE-9188) BloomFilter support in ORC

["Prasanth Jayachandran (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-9188?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14304282#comment-14304282 ] 

Prasanth Jayachandran commented on HIVE-9188:
---------------------------------------------

Updated Indexes section in ORC spec with bloom filter information.
https://cwiki.apache.org/confluence/display/Hive/LanguageManual+ORC#LanguageManualORC-Indexes

[~owen.omalley] can you take a look at the spec? Also the new patch.

> BloomFilter support in ORC
> --------------------------
>
>                 Key: HIVE-9188
>                 URL: https://issues.apache.org/jira/browse/HIVE-9188
>             Project: Hive
>          Issue Type: New Feature
>          Components: File Formats
>    Affects Versions: 0.15.0
>            Reporter: Prasanth Jayachandran
>            Assignee: Prasanth Jayachandran
>              Labels: orcfile
>         Attachments: HIVE-9188.1.patch, HIVE-9188.2.patch, HIVE-9188.3.patch, HIVE-9188.4.patch, HIVE-9188.5.patch, HIVE-9188.6.patch, HIVE-9188.7.patch
>
>
> BloomFilters are well known probabilistic data structure for set membership checking. We can use bloom filters in ORC index for better row group pruning. Currently, ORC row group index uses min/max statistics to eliminate row groups (stripes as well) that do not satisfy predicate condition specified in the query. But in some cases, the efficiency of min/max based elimination is not optimal (unsorted columns with wide range of entries). Bloom filters can be an effective and efficient alternative for row group/split elimination for point queries or queries with IN clause.



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