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https://issues.apache.org/jira/browse/CASSANDRA-1555?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12967060#action_12967060
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Stu Hood commented on CASSANDRA-1555:
-------------------------------------
* If BloomFilter is likely to be deprecated in favor of BigBloomFilter, naming
them LegacyBloomFilter and BloomFilter might reduce the surface area of future
changes
* Probably a good opportunity to improve the serialization of BigBloomFilter:
Java serialization is very wasteful for space (each row would contain the
string "org.apache.cassandra.utils.obs.OpenBitSet"). Instead, just serializing
an OpenBitSet as a {{long[]}} and # of valid bits would be much better
* (Big)BloomFilter
* maxBucketsPerElement can be pushed up into Filter
* getFilter could probably be pushed up to filter, or at least removed from
BloomFilter
* emptyBuckets is unused
* Orphaned method BigBloomFilter.serializeBitSet
* Indentation is off in SSTableReader and BigBloomFilter
I'm working on a separate issue to refresh LegacySSTableTest to check the
column-level bloom filters as well: see CASSANDRA-1822
> Considerations for larger bloom filters
> ---------------------------------------
>
> Key: CASSANDRA-1555
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1555
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Stu Hood
> Assignee: Ryan King
> Fix For: 0.8
>
> Attachments: cassandra-1555.tgz, CASSANDRA-1555v2.patch
>
>
> To (optimally) support SSTables larger than 143 million keys, we need to
> support bloom filters larger than 2^31 bits, which java.util.BitSet can't
> handle directly.
> A few options:
> * Switch to a BitSet class which supports 2^31 * 64 bits (Lucene's OpenBitSet)
> * Partition the java.util.BitSet behind our current BloomFilter
> ** Straightforward bit partitioning: bit N is in bitset N // 2^31
> ** Separate equally sized complete bloom filters for member ranges, which can
> be used independently or OR'd together under memory pressure.
> All of these options require new approaches to serialization.
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