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https://issues.apache.org/jira/browse/PARQUET-2366?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17780789#comment-17780789
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ASF GitHub Bot commented on PARQUET-2366:
-----------------------------------------
wgtmac merged PR #1174:
URL: https://github.com/apache/parquet-mr/pull/1174
> Optimize random seek during rewriting
> -------------------------------------
>
> Key: PARQUET-2366
> URL: https://issues.apache.org/jira/browse/PARQUET-2366
> Project: Parquet
> Issue Type: Improvement
> Reporter: Xianyang Liu
> Priority: Major
>
> The `ColunIndex`, `OffsetIndex`, and `BloomFilter` are stored at the end of
> the file. We need to randomly seek 4 times when rewriting a column chunk. We
> found this could impact the rewrite performance heavily for files with a
> number of columns(~1000). In this PR, we read the `ColumnIndex`,
> `OffsetIndex`, and `BloomFilter` into a cache to avoid the random seek. We
> got about 60 times performance improvement in production environments for the
> files with about one thousand columns.
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