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https://issues.apache.org/jira/browse/HBASE-11581?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14090340#comment-14090340
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stack commented on HBASE-11581:
-------------------------------
Thanks [~jmhsieh] for review.
A better way to do this, a more 'natural' way is fixing the 'Cache DATA on
Read' flag. Currently it is overloaded, compounded with the BLOCKCACHE =>
true/false flag. It needs to be made distinct. I just tried on a table
setting CF to false but BC got deployed anyways.
{code}
hbase(main):004:0> enable 'TestTable'
0 row(s) in 0.8470 seconds
hbase(main):005:0> describe 'TestTable'
DESCRIPTION
ENABLED
'TestTable', {NAME => 'info', DATA_BLOCK_ENCODING => 'NONE', BLOOMFILTER =>
'ROW', REPLICATION_SCOPE => '0', VERSIONS => '2', COMP true
RESSION => 'NONE', MIN_VERSIONS => '0', TTL => 'FOREVER', KEEP_DELETED_CELLS
=> 'false', BLOCKSIZE => '65536', IN_MEMORY => 'false
', BLOCKCACHE => 'false'}
1 row(s) in 0.0430 seconds
hbase(main):006:0>
hbase(main):007:0*
hbase(main):008:0* disable 'TestTable'
0 row(s) in 1.2930 seconds
hbase(main):009:0> describe 'TestTable'
DESCRIPTION
ENABLED
'TestTable', {NAME => 'info', DATA_BLOCK_ENCODING => 'NONE', BLOOMFILTER =>
'ROW', REPLICATION_SCOPE => '0', VERSIONS => '2', COMP false
RESSION => 'NONE', MIN_VERSIONS => '0', TTL => 'FOREVER', KEEP_DELETED_CELLS
=> 'false', BLOCKSIZE => '65536', IN_MEMORY => 'false
', BLOCKCACHE => 'false'}
1 row(s) in 0.0340 seconds
hbase(main):010:0> alter 'TestTable', {NAME => 'info', BLOCKCACHE => false}
Updating all regions with the new schema...
16/16 regions updated.
Done.
0 row(s) in 1.1950 seconds
hbase(main):011:0> describe 'TestTable'
DESCRIPTION
ENABLED
'TestTable', {NAME => 'info', DATA_BLOCK_ENCODING => 'NONE', BLOOMFILTER =>
'ROW', REPLICATION_SCOPE => '0', VERSIONS => '2', COMP false
RESSION => 'NONE', MIN_VERSIONS => '0', TTL => 'FOREVER', KEEP_DELETED_CELLS
=> 'false', BLOCKSIZE => '65536', IN_MEMORY => 'false
', BLOCKCACHE => 'false'}
1 row(s) in 0.0330 seconds
hbase(main):012:0> enable 'TestTable'
0 row(s) in 0.7850 seconds
{code}
> Add option so CombinedBlockCache L2 can be null (fscache)
> ---------------------------------------------------------
>
> Key: HBASE-11581
> URL: https://issues.apache.org/jira/browse/HBASE-11581
> Project: HBase
> Issue Type: New Feature
> Components: BlockCache
> Reporter: stack
> Assignee: stack
> Priority: Minor
> Labels: beginner, beginners
> Attachments: 11581.txt
>
>
> Add option, mostly for comparison's sake, that allows a deploy orchestrated
> by CombinedBlockCache such that its L1 is LruBlockCache for META blocks but
> DATA blocks are fetched each time (we don't try and cache them, no blockcache
> churn).
> In operation, i can see fscache coming around to cover the fetched DATA
> blocks such that if the DATA blocks fit in fscache, seeks go to zero.
> This setup for sure runs slower. Will publish numbers elsewhere. Meantime,
> here is a patch to enable this option.
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