You are viewing a plain text version of this content. The canonical link for it is here.

Posted to dev@parquet.apache.org by "Micah Kornfield (Jira)" <ji...@apache.org> on 2022/05/10 04:14:00 UTC

[jira] [Commented] (PARQUET-2122) Adding Bloom filter to small Parquet file bloats in size X1700

    [ https://issues.apache.org/jira/browse/PARQUET-2122?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17534123#comment-17534123 ] 

Micah Kornfield commented on PARQUET-2122:
------------------------------------------

I believe the answer is the Bloom filter implementation isn't adaptive, so it simply preallocates all the bytes necessary.  It would certainly be a nice option to have more adaptive data structures that can scale down for smaller files but is probably a decent amount of work to build consensus around this.

> Adding Bloom filter to small Parquet file bloats in size X1700
> --------------------------------------------------------------
>
>                 Key: PARQUET-2122
>                 URL: https://issues.apache.org/jira/browse/PARQUET-2122
>             Project: Parquet
>          Issue Type: Bug
>          Components: parquet-cli, parquet-mr
>    Affects Versions: 1.13.0
>            Reporter: Ze'ev Maor
>            Priority: Critical
>         Attachments: data.csv, data_index_bloom.parquet
>
>
> Converting a small, 14 rows/1 string column csv file to Parquet without bloom filter yields a 600B file, adding '.withBloomFilterEnabled(true)' to ParquetWriter then yields a 1049197B file.
> It isn't clear what the extra space is used by.
> Attached csv and bloated Parquet files.



--
This message was sent by Atlassian Jira
(v8.20.7#820007)