Bypass the BlockCache
You can bypass the BlockCache if the data needed for a specific but atypical operation does not all fit in memory.
For an
atypical operation does not all fit in memory, using the BlockCache can be
counter-productive because data that you are still using may be evicted, or even if other
data is not evicted, excess garbage collection can adversely effect performance. For this
type of operation, you may decide to bypass the BlockCache. To bypass the BlockCache for a
given Scan or Get, use the setCacheBlocks(false) method.
In addition, you can prevent a specific column family's contents from
being cached, by setting its
BLOCKCACHE configuration
to false. Use the following syntax in HBase
Shell:hbase> alter 'myTable', CONFIGURATION => {NAME => 'myCF', BLOCKCACHE => 'false'}