Elliott Clark created HBASE-13643:
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Summary: Follow Google to get more 9's
Key: HBASE-13643
URL: https://issues.apache.org/jira/browse/HBASE-13643
Project: HBase
Issue Type: Improvement
Reporter: Elliott Clark
Ideas taken shamelessly from Google's HBasecon talk
(http://hbasecon.com/agenda/):
On failover all regions are unavailable for reads (and sometime writes) until
after all write ahead logs have been recovered. To combat that the last flushed
seqid is kept around. These writes to meta
Google took this one step farther and set some regions (Tablets in BigTable) as
read only. Setting a region as read only means there's no memstore. No need to
flush before move, split, or merge.
In addition to the wins that Google got, HBase would also be able to shed some
memory pressure. Right now every region gets a memstore and with that memstore
comes a mslab. Read only regions would not need these added object. This should
allow a regionserver to host lots of cold regions without too much memory
pressure.
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