Liu Shaohui created HBASE-11536:
-----------------------------------
Summary: Puts of region location to Meta may be out of order which
causes inconsistent of region location
Key: HBASE-11536
URL: https://issues.apache.org/jira/browse/HBASE-11536
Project: HBase
Issue Type: Bug
Components: Region Assignment
Reporter: Liu Shaohui
Priority: Critical
In product hbase cluster, we found inconsistency of region location in the meta
table. Region cdfa2ed711bbdf054d9733a92fd43eb5 is onlined in regionserver
10.237.12.13:11600 but the region location in Meta table is 10.237.12.15:11600.
This is because of the out-of-order puts for meta table.
# HMaster try to assign the region to 10.237.12.15:11600.
# RegionServer: 10.237.12.15:11600. During the opening the region, the put of
region location(10.237.12.15:11600) to meta table is timeout(60s) and the
htable retry for second time. (regionserver serving meta has got the request of
the put. The timeout is beause ther is a bad disk in this regionserver and
sync of hlog is very slow.
)
During the retry in htable, the OpenRegionHandler is timeout(100s) and the
PostOpenDeployTasksThread is interrupted. Through the htable is closed in the
MetaEditor finally, the share connection the htable used is not closed and the
call of put for meta table is on-flying in the connection. Assumed that this
on-flying call of put to meta is named call A.
# RegionServer: 10.237.12.15:11600. For the timeout of OpenRegionHandler, the
OpenRegionHandler marks the assign state of this region to FAILED_OPEN.
# HMaster watchs this event of FAILED_OPEN and assigns the region to another
regionserver: 10.237.12.13:11600
# RegionServer: 10.237.12.13:11600. This regionserver opens the region
successfully . Assumed that the put of region location(10.237.12.13:11600) to
meta table in this regionserver is named B.
There is no order guarantee for call A and B. If call A is processed after call
B in regionserver serving meta region, the region location in meta table will
be wrong.
>From the raw scan of meta table we found:
{code}
scan '.META.', {RAW => true, LIMIT => 1, VERSIONS => 10, STARTROW =>
'xxx.adfa2ed711bbdf054d9733a92fd43eb5.'}
{code}
{quote}
xxx.adfa2ed711bbdf054d9733a92fd43eb5. column=info:server,
timestamp=1404885460553(=> Wed Jul 09 13:57:40 +0800 2014),
value=10.237.12.15:11600 --> Retry put from 10.237.12.15
xxx.adfa2ed711bbdf054d9733a92fd43eb5. column=info:server,
timestamp=1404885456731(=> Wed Jul 09 13:57:36 +0800 2014),
value=10.237.12.13:11600 --> put from 10.237.12.13
xxx.adfa2ed711bbdf054d9733a92fd43eb5. column=info:server,
timestamp=1404885353122( Wed Jul 09 13:55:53 +0800 2014),
value=10.237.12.15:11600 --> First put from 10.237.12.15
{quote}
Related hbase log is attached in this issue and disscusions are welcomed.
For there is no order guarantee for puts from different htables, one solution
for this issue is to give an increased id for each assignment of a region and
use this id as the timestamp of put of region location to meta table. The
region location with large assign id will be got by hbase clients.
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