[
https://issues.apache.org/jira/browse/HBASE-12629?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14235192#comment-14235192
]
Jonathan Hsieh commented on HBASE-12629:
----------------------------------------
For users or operators, if a feature isn't documented it doesn't exist and the
default is the only behavior. That's one vote for removing the knob.
I went and rereviewed HBASE-10413 -- the patch that introduces the
RegionSizeCalculator and adds the info the the InputSplit's getLength() call.
This doesn't affect the NN -- the data is gathered from ClusterStats -- at most
an rpc that gathers metric info from the HMaster. (I guess I can see a case in
the futre when this could be a problem).
As a nit, implementation-wise the check on whether to do anything useful is
inside the RegionSizeCalculator seems wrong. Instead of having
RegionSizeCalculator decide internally whether it is enabled/disabled, it
should be done by either:
1) removing the knob so that you always have the ClusterStatus based
RegionSizeCalculator (the first patch here)
2) having an "AlwaysZeroRegionSizeCalculator" and a
"ClusterStatusRegionSizeCaculator" and leave making the decision logic for the
TableInputFormatBase/MultiTableInputFormat code.
FYI, the patch I'm looking at -- HBASE-12590 -- rejiggers MR InputSplit ranges
to deskew region splits for MR jobs and explicitly relies on the region size
calculation. Having the ClusterStatus based RegionSizeCalc on is a prereq and
leaving the ability disable it adds a odd corner case and more testing
associated with it. Seems better to just have one knob for this. This leads
to:
1) Just removing that rscalc config so we have one knob using the the
HBASE-12590 deskew is used.
2) An alternative where we refactor instead of remove and have the HBASE-12590
patch decides on the to pick the "ClusterStatusRegionSizeCalculator" if enabled
or "AlwaysZeroRSCalc" if not enabled. We'd combine HBASE-12590 and
HBASE-10413's features into one config knob (instead of what currently would be
two). If after some testing HBASE-12590 works nicely, I think I'd want it on
by default as well.
WDYT?
> Remove hbase.regionsizecalculator.enable from RegionSizeCalculator
> ------------------------------------------------------------------
>
> Key: HBASE-12629
> URL: https://issues.apache.org/jira/browse/HBASE-12629
> Project: HBase
> Issue Type: Improvement
> Reporter: Jonathan Hsieh
> Assignee: Jonathan Hsieh
> Fix For: 1.0.0, 2.0.0
>
> Attachments:
> 0001-HBASE-12629-Remove-hbase.regionsizecalculator.enable.patch
>
>
> The RegionSizeCalculator has a option to disable it. It is on by default and
> end-to-end use with it disabled is not tested or used anywhere except for a
> simple unit test. This removes it.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
