Hi James, Executing the alter table query in the format you specified indeed shows the BLOCKCACHE => 'false' when describing the table on hbase shell.
Thanks, Amit. On Fri, Mar 25, 2016 at 10:57 PM, James Taylor <[email protected]> wrote: > Hi Amit, > > Have you see our documentation and examples for ALTER TABLE [1]? > > So you could do ALTER TABLE my_table SET BLOCKCACHE=false; > > If you want to prevent rows from being put in the block cache on a per > query basis, you can use the /*+ NO_CACHE */ hint [2] on a query like this: > > SELECT /*+ NO_CACHE */ ... > > Thanks, > James > > [1] https://phoenix.apache.org/language/index.html#alter > [2] https://phoenix.apache.org/language/index.html#hint > > On Fri, Mar 25, 2016 at 6:39 AM, Amit Shah <[email protected]> wrote: > >> I noticed that the charts <http://i.imgur.com/ZEJTHWt.png>on cloudera >> indicate no block usage when the group by query is executed. This probably >> means that the block cache is disabled. The only strange fact is that the >> hbase shell describe command gave BLOCKCACHE => 'true'. It would be great >> if someone could throw some light on this. >> >> P.S - Though disabling the block cache didn't speed up the group by query >> but that seems like a separate topic of discussion. >> >> Thanks! >> >> On Fri, Mar 25, 2016 at 1:34 PM, Amit Shah <[email protected]> wrote: >> >>> Hi, >>> >>> I am using apache hbase (version 1.0.0) and phoenix (version 4.6) >>> deployed through cloudera. Since my aggregations with group by query is >>> slow, I want to try out disabling the block cache for a particular hbase >>> table. I tried a couple of approaches but couldn't succeed. I am verifying >>> if the block cache is enabled/disabled through the hbase shell - describe >>> 'my_table' command. >>> >>> 1. Set 'hfile.block.cache.size' property from cloudera console to 0 >>> >>> 2. alter 'myTable', CONFIGURATION => {NAME => 'myColumnFamily', >>> BLOCKCACHE => 'false'} >>> >>> Even after the above two steps, I get BLOCKCACHE => 'true' in the >>> describe command output >>> >>> COLUMN FAMILIES DESCRIPTION {NAME => '0', DATA_BLOCK_ENCODING => >>> 'FAST_DIFF', BLOOMFILTER => 'ROW', REPLICATION_SCOPE => '0', COMPRESSION => >>> 'NONE', VERSIONS => '1', MIN_VERSIONS => '0', TTL => 'FOREVER', >>> KEEP_DELETED_CELLS => 'FALSE', BLOCKSIZE => '65536', IN_MEMORY => 'false', >>> BLOCKCACHE => 'true'} >>> >>> What could be going wrong? Any suggestions? >>> >>> Thank you. >>> >>> >>> >> >
