[
https://issues.apache.org/jira/browse/HBASE-13991?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14621502#comment-14621502
]
Ben Lau commented on HBASE-13991:
---------------------------------
Hi stack, we did consider doing an online migration from the old format to the
new one, but it would require messy changes to the codebase and be tricky to
test fully. That's because whenever you access a region's contents you would
have to test for both the humongous and non-humongous path contents instead of
just using what you know it to be. Also there's a lot more going on during an
online migration, regions can be moving, splitting, recovering from normal
cluster operation and testing that an online migration works in all cases would
be tricky. This can be ameliorated to some extent by making the migration
'mostly online', i.e. offlining regions, migrating them, then re-opening them.
For Yahoo’s use case, an online migration is not necessary but if the community
really needs it we could look into it.
[~toffer] can comment more, but I believe we would prefer to insert the buckets
under the table directory for now and gradually transition later to reworking
meta to be the source of table/region association information, creating a
uniform/non-table oriented data directory, etc.
> Hierarchical Layout for Humongous Tables
> ----------------------------------------
>
> Key: HBASE-13991
> URL: https://issues.apache.org/jira/browse/HBASE-13991
> Project: HBase
> Issue Type: Sub-task
> Reporter: Ben Lau
> Assignee: Ben Lau
> Attachments: HBASE-13991-master.patch, HumongousTableDoc.pdf
>
>
> Add support for humongous tables via a hierarchical layout for regions on
> filesystem.
> Credit for most of this code goes to Huaiyu Zhu.
> Latest version of the patch is available on the review board:
> https://reviews.apache.org/r/36029/
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
