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https://issues.apache.org/jira/browse/PARQUET-2254?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17702456#comment-17702456
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ASF GitHub Bot commented on PARQUET-2254:
-----------------------------------------
yabola commented on PR #1042:
URL: https://github.com/apache/parquet-mr/pull/1042#issuecomment-1475678398
5 candidates are set by default, and 2M storage is occupied by default (the
previous default was 1M):
`[expectedNDV=540000, numBytes=65536],[expectedNDV=108000,
numBytes=131072],[expectedNDV=216500, numBytes=262144],
[expectedNDV=433000, numBytes=524288],[expectedNDV=866000, numBytes=1048576]`
> Build a BloomFilter with a more precise size
> --------------------------------------------
>
> Key: PARQUET-2254
> URL: https://issues.apache.org/jira/browse/PARQUET-2254
> Project: Parquet
> Issue Type: Improvement
> Reporter: Mars
> Assignee: Mars
> Priority: Major
>
> h3. Why are the changes needed?
> Now the usage of bloom filter is to specify the NDV(number of distinct
> values), and then build BloomFilter. In general scenarios, it is actually not
> sure how much the distinct value is.
> If BloomFilter can be automatically generated according to the data, the file
> size can be reduced and the reading efficiency can also be improved.
> h3. What changes were proposed in this pull request?
> {{DynamicBlockBloomFilter}} contains multiple {{BlockSplitBloomFilter}} as
> candidates and inserts values in the candidates at the same time. Use the
> largest bloom filter as an approximate deduplication counter, and then remove
> incapable bloom filter candidates during data insertion.
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