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https://issues.apache.org/jira/browse/PARQUET-2260?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17703845#comment-17703845
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ASF GitHub Bot commented on PARQUET-2260:
-----------------------------------------
yabola commented on code in PR #1043:
URL: https://github.com/apache/parquet-mr/pull/1043#discussion_r1145564119
##########
parquet-column/src/main/java/org/apache/parquet/column/impl/ColumnWriterBase.java:
##########
@@ -97,7 +97,7 @@ abstract class ColumnWriterBase implements ColumnWriter {
int optimalNumOfBits =
BlockSplitBloomFilter.optimalNumOfBits(ndv.getAsLong(), fpp.getAsDouble());
this.bloomFilter = new BlockSplitBloomFilter(optimalNumOfBits / 8,
maxBloomFilterSize);
} else {
- this.bloomFilter = new BlockSplitBloomFilter(maxBloomFilterSize);
+ this.bloomFilter = BlockSplitBloomFilter.of(maxBloomFilterSize);
Review Comment:
> If I understand something wrong, please correct me. I found this part of
code, need `bitset.length / BYTES_PER_BLOCK` result to be integer, need power
of 2, extra bit is useless, but also no error.
@wgtmac @gszadovszky Sorry, I may have misunderstood. `bitset.length` is
valid as long as it is a multiple of `BYTES_PER_BLOCK`(32) (not necessarily a
power of 2) .
The reason for the power of 2 here is more complicated, I think there are
performance reasons.
Most of the existing parquet uses need to specify the NDV value or default
maxBytes 1MB. In these cases, `numbytes` will be always initialized to a power
of 2.
@chenjunjiedada could you help take a look at this? thank you.
> Bloom filter bytes size shouldn't be larger than maxBytes size in the
> configuration
> ------------------------------------------------------------------------------------
>
> Key: PARQUET-2260
> URL: https://issues.apache.org/jira/browse/PARQUET-2260
> Project: Parquet
> Issue Type: Bug
> Reporter: Mars
> Assignee: Mars
> Priority: Major
>
> Before this PR: If {{parquet.bloom.filter.max.bytes}} configuration is not a
> power of 2 value, the size of the bloom filter generated will exceed this
> value. For example, now if set {{parquet.bloom.filter.max.bytes}} as 1024 *
> 1024+1= 1048577 , the bytes size of bloom filter generated will be 1024 *
> 1024 * 2 = 2097152. This does not match the definition of the parameter
> After this PR: set this value to the largest power of two less than
> {{parquet.bloom.filter.max.bytes}} and It should be 1024 * 1024
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