IN_MEMORY means that HBase will try really hard to keep all of the data blocks for a table in the block cache. Block cache is expired on a LRU basis in three priority bands. Blocks for IN_MEMORY tables have the highest priority. They will be the last to be evicted.
It does not mean data is never written to disk -- all data in HBase is backed by files in HDFS. It does not mean the table data won't be evicted if the table becomes very large and it cannot all fit in the available configured block cache. Best regards, - Andy Problems worthy of attack prove their worth by hitting back. - Piet Hein (via Tom White) ----- Original Message ----- > From: Weiwei Xiong <[email protected]> > To: [email protected] > Cc: > Sent: Friday, July 8, 2011 6:04 PM > Subject: IN_MEMORY setting > > Hi all, > > Is there anyway to always keep a table in memory? Will IN_MEMORY setting > server this purpose? > > Thanks, > ww >
