Thanks, Minh. This blog also mentions that bloom filters check "if a given column exists in a given row". However in "HBase: The definitive guide" it is mentioned that "enabling the Bloom filter does give you the immediate advantage of knowing if a file contains a particular row key or not". Is the blog post a bit outdated?
Thanks, Sever On Wed, Jun 27, 2012 at 6:00 PM, Minh Duc Nguyen <[email protected]> wrote: > Sever, the IN_MEMORY option doesn't change when table content is > transferred into RAM. Whether set to true or false, the blocks of > data are only loaded into memory after a normal retrieval operation. > When IN_MEMORY is set to true, HBase just tries to keep data in memory > more aggressively than it normally would. This wiki explains it in > more detail: > > > http://jimbojw.com/wiki/index.php?title=Understanding_HBase_column-family_performance_options > > ~ Minh > > On Wed, Jun 27, 2012 at 7:18 AM, Sever Fundatureanu > <[email protected]> wrote: > > Hello, > > > > I initially created a table without the IN_MEMORY option enabled and > loaded > > some data into it. Then I disabled it, modified the IN_MEMORY option > using > > the hbase shell 'alter' command, re-enabled it and finally ran a major > > compaction. I do notice now the memory usage of the region servers has > > increased. However for some queries I am still getting faster responses > > only the 2nd time, as if I'm hitting the cache. Can someone tell me when > > does the table content get transferred into RAM if IN_MEMORY option is > > enabled like above? > > > > Thank you, > > -- > > Sever Fundatureanu > > > > Vrije Universiteit Amsterdam > > E-mail: [email protected] > -- Sever Fundatureanu Vrije Universiteit Amsterdam Tel: +31644329534 E-mail: [email protected]
