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GGJ
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Posts: 3
Registered: ‎03-02-2015

How to figure out if Hbase read operations are using BloomFilters?

I am using version 0.94.2-cdh4.2.1 of HBase. I use Scan method with start and end row key being the same which means I want to fetch a single row. I also specify QualifierFilter which indicates the Column I am interested in.

I did not have bloom filters enabled so far but I read in hbase book (http://hbase.apache.org/book.html) that bloom filters are supposed to help improve performance; so I am doing that now. I enable ROWCOL bloomfilter on my table. But I do not see any noticeable improvement in perf on my perf test.

  1. In my situation of using Scan, is the bloom filter going to be applied at all? Per documentation it looks like No but I am not sure.

  2. There is a method addColumn in Scan/Get operations to specify which columns I am interested in fetching.

https://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/Get.html

Is bloom filter application depending on whether I use QualifierFilter or whether I use the addColumn method?

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Registered: ‎07-31-2013

Re: How to figure out if Hbase read operations are using BloomFilters?

No, Bloom Filters apply only to random reads, not for range scans (these are not row lookups, but a more direct read).

The Bloom Filter also does not depend on use of a QualifierFilter, but your actual sought columns instead (i.e., a yes to addColumn).
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