[
https://issues.apache.org/jira/browse/HBASE-15075?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15093126#comment-15093126
]
Ted Yu commented on HBASE-15075:
--------------------------------
bq. The description on this issue implies something generic
When I logged this JIRA, that was the intention. However, working out a patch,
I realized that the metadata has to go through RPC layer using protobuf. This
narrows the choice for the data type used.
Subject of the JIRA can be modified to reflect the actual approach.
bq. Why use UUID? Why not a random long?
UUID gives us wider scope for the purpose of identification of split requests.
Meaning, for long running region servers, the chance of collision between UUIDs
is very low. As for type long, the chance of collision is higher.
bq. Should we add API so split requests can pass arbitrary metadata as issue
description implies?
I would be willing to see how the arbitrary metadata should be formulated. Keep
in mind that such metadata needs to be protobuf'ed.
For the use cases I am aware of, UUID suffices.
bq. Should every request type be extended like this? I.e. merge transactions?
Depending on the outcome of discussion for this JIRA, I think the adopted
solution can be applied for merge request as well (maybe in another JIRA).
> Allow region split request to carry metadata
> --------------------------------------------
>
> Key: HBASE-15075
> URL: https://issues.apache.org/jira/browse/HBASE-15075
> Project: HBase
> Issue Type: Improvement
> Reporter: Ted Yu
> Assignee: Ted Yu
> Attachments: 15075-v0.txt, 15075-v1.txt, 15075-v2.txt,
> HBASE-15075.v2.patch, HBASE-15075.v3.patch
>
>
> During the process of improving region normalization feature, I found that if
> region split request triggered by the execution of SplitNormalizationPlan
> fails, there is no way of knowing whether the failed split originated from
> region normalization.
> The association of particular split request with outcome of split would give
> RegionNormalizer information so that it can make better normalization
> decisions in the subsequent invocations.
> One approach is to embed metadata in SplitRequest which gets passed through
> RegionStateTransitionContext when
> RegionServerServices#reportRegionStateTransition() is called.
> This way, RegionStateListener can be notified with the metadata (id of the
> requester).
> See discussion on dev mailing list
> http://search-hadoop.com/m/YGbbCXdkivihp2
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
