[
https://issues.apache.org/jira/browse/HBASE-3789?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Jean-Daniel Cryans updated HBASE-3789:
--------------------------------------
Attachment: HBASE-3789-v3-0.90.patch
With the previous patch all the tests passed except for hbck. Looking deeper, I
see hbck creates it's own znodes so now the master doesn't see that. It's not
clear to my why it's not using HBA.assign instead of the trickery with the
HBCK_CODE_NAME.
This patch modifies hbck so that it uses "normal" tools provided by the master
instead of bypassing it.
I'm also working on porting that to trunk. I got the previous patch I posted
working but didn't do the hbck stuff yet because it's different.
Also I still didn't touch the splitting code in trunk.
> Cleanup the locking contention in the master
> --------------------------------------------
>
> Key: HBASE-3789
> URL: https://issues.apache.org/jira/browse/HBASE-3789
> Project: HBase
> Issue Type: Improvement
> Affects Versions: 0.90.2
> Reporter: Jean-Daniel Cryans
> Assignee: Jean-Daniel Cryans
> Priority: Blocker
> Fix For: 0.92.0
>
> Attachments: HBASE-3789-v2-0.90.patch, HBASE-3789-v3-0.90.patch,
> HBASE-3789.patch
>
>
> The new master uses a lot of synchronized blocks to be safe, but it only
> takes a few jstacks to see that there's multiple layers of lock contention
> when a bunch of regions are moving (like when the balancer runs). The main
> culprits are regionInTransition in AssignmentManager, ZKAssign that uses
> ZKW.getZNnodes (basically another set of region in transitions), and locking
> at the RegionState level.
> My understanding is that even tho we have multiple threads to handle regions
> in transition, everything is actually serialized. Most of the time, lock
> holders are talking to ZK or a region server, which can take a few
> milliseconds.
> A simple example is when AssignmentManager wants to update the timers for all
> the regions on a RS, it will usually be waiting on another thread that's
> holding the lock while talking to ZK.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
