46e53b089a
In HBASE-8370 "Report data block cache hit rates apart from aggregate cache hit rates" discussion highlights small changes in caching percentage can make for large changes in cache contents; e.g. lots of data blocks may be getting evicited but because meta blocks -- index and blooms -- are staying in cache with high hit rates, a large data block eviction may show as a small change in overall cache percentage (e.g. from 99.99 to 99.11). Changes the getBlockCacheHitPercent from an int to a double. Also changes name of the jmx metric blockCountHitPercent to be blockCacheCountHitPercent instead. May be incompatible change.
Apache HBase [1] is an open-source, distributed, versioned, column-oriented store modeled after Google' Bigtable: A Distributed Storage System for Structured Data by Chang et al.[2] Just as Bigtable leverages the distributed data storage provided by the Google File System, HBase provides Bigtable-like capabilities on top of Apache Hadoop [3]. To get started using HBase, the full documentation for this release can be found under the doc/ directory that accompanies this README. Using a browser, open the docs/index.html to view the project home page (or browse to [1]). The hbase 'book' at http://hbase.apache.org/book.html has a 'quick start' section and is where you should being your exploration of the hbase project. The latest HBase can be downloaded from an Apache Mirror [4]. The source code can be found at [5] The HBase issue tracker is at [6] Apache HBase is made available under the Apache License, version 2.0 [7] The HBase mailing lists and archives are listed here [8]. The HBase distribution includes cryptographic software. See the export control notice here [9]. 1. http://hbase.apache.org 2. http://labs.google.com/papers/bigtable.html 3. http://hadoop.apache.org 4. http://www.apache.org/dyn/closer.cgi/hbase/ 5. http://hbase.apache.org/docs/current/source-repository.html 6. http://hbase.apache.org/docs/current/issue-tracking.html 7. http://hbase.apache.org/docs/current/license.html 8. http://hbase.apache.org/docs/current/mail-lists.html 9. http://hbase.apache.org/docs/current/export-notice.html