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From "Owen O'Malley (JIRA)" <>
Subject [jira] [Commented] (HIVE-9188) BloomFilter in ORC row group index
Date Wed, 07 Jan 2015 18:33:34 GMT


Owen O'Malley commented on HIVE-9188:

I'm concerned about the size of the bloom filters and making them an integrated part of the
column statistics. I think we'd do much better to make a BLOOM_FILTER stream kind and place
them in a completely separate stream. That would allow the predicate push down to only load
the bloom filters for the columns that it needs.

> BloomFilter in ORC row group index
> ----------------------------------
>                 Key: HIVE-9188
>                 URL:
>             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
> 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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