[
https://issues.apache.org/jira/browse/HBASE-4455?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13113887#comment-13113887
]
[email protected] commented on HBASE-4455:
------------------------------------------------------
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. > Great stuff! I have some questions throughout but seems like this will
make everything more resilient to root/meta servers failing. Is the general
approach to always verify / always check rather than relying on cached
locations or values?
bq. >
bq. > Have you thought about any ways that we could add some better unit tests
around this stuff? There's a TestRollingRestart that is obviously not good
enough :)
The repro of such bug depends on timing of events. Initially I thought perhaps
we can inject timeout into various places in the code. At this point, it is
easier to just do the testing on a small cluster and eventually the bug will
appear. Perhaps something we can work on later.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/catalog/CatalogTracker.java,
line 309
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45299#file45299line309>
bq. >
bq. > why log the cached META server here? didn't we just verify that it
was not valid?
Fixed.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/catalog/CatalogTracker.java,
line 310
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45299#file45299line310>
bq. >
bq. > why log the cached meta location here? it might be confusing since
it doesn't log that we just found this meta location was invalid
Fixed.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java,
line 2532
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45300#file45300line2532>
bq. >
bq. > add another * here, so: /**
bq. >
bq. > that ensure this gets picked up as javadoc
Fixed.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java,
line 2558
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45300#file45300line2558>
bq. >
bq. > this looks like a random debug statement, what does matchZK, sn:
server mean?
Fixed.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/zookeeper/RootRegionTracker.java,
lines 62-69
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45309#file45309line62>
bq. >
bq. > why this change? should this be rolled into the ZKNodeTracker
rather than overriding the getData() behavior?
Fixed.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/zookeeper/RootRegionTracker.java,
line 90
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45309#file45309line90>
bq. >
bq. > it seems like you're covering up for bugs in the underlying
ZKNodeTracker... can we fix that instead? or if it's a matter of returning a
cached value or not, can we just add a boolean flag for refresh/nocache?
Fixed.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/catalog/CatalogTracker.java,
line 294
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45299#file45299line294>
bq. >
bq. > so we always verify the connection now?
Before the fix, all callers set it to "true". So there is no behavior change.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/catalog/CatalogTracker.java,
line 368
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45299#file45299line368>
bq. >
bq. > why do we have two hard-coded timeouts in this area of code? :)
bq. >
bq. > this code seems to always sleep 500ms at a time unless you set
timeout=0 and then it loops every 50ms? that doesn't seem right... i could set
timeout to 100ms and it would sleep 500ms. sleeping 50ms every time would be
better but there's probably a solution with less overhead (doing remote read
queries every 50ms in a loop)
bq. >
bq. > could we just notifyAll() on metaAvailable whenever we relocate root?
Choose the min(500ms, timeout) at this point, given we might do more code
cleanup around RootRegionTracker later.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/handler/ServerShutdownHandler.java,
line 215
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45304#file45304line215>
bq. >
bq. > i'm also a bit confused by this. couldn't we just increase the
thread pool size to 2? :)
Added more explanation in the ServerShutdownHandler.java about the scenario.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java,
line 2533
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45300#file45300line2533>
bq. >
bq. > what about this method is specific to the shutdown server? this
seems specific about regions in transition. if we only use it in the context
of servers being shut down then maybe name it accordingly? it does seem like a
generally useful method though and just related to ZK (could put it in a ZK
util class?)
This method uses states in ZK and AssignmentManager. So it seems better to keep
it in AssignmentManager. Keep the name given it might be useful outside
shutdown scenario.
bq. On 2011-09-23 08:17:29, Jonathan Gray wrote:
bq. >
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/handler/CloseRegionHandler.java,
line 144
bq. > <https://reviews.apache.org/r/2007/diff/2/?file=45306#file45306line144>
bq. >
bq. > is this normal? should it be a warn? maybe a comment on why this
would happen
This could happen when the RS shutdowns. When RS shutdowns, setClosedState will
try to transition from CLOSING state to CLOSED. That will fail given the
original state is OPENED instead of CLOSING.
Normally when AssignmentManager tries to close a region, it will first set the
node to CLOSING before RPC call to RS. In that scenario, setClosedState will
return successful.
- Ming
-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/2007/#review2037
-----------------------------------------------------------
On 2011-09-24 01:50:02, Ming Ma wrote:
bq.
bq. -----------------------------------------------------------
bq. This is an automatically generated e-mail. To reply, visit:
bq. https://reviews.apache.org/r/2007/
bq. -----------------------------------------------------------
bq.
bq. (Updated 2011-09-24 01:50:02)
bq.
bq.
bq. Review request for hbase.
bq.
bq.
bq. Summary
bq. -------
bq.
bq. 1. Add more logging.
bq. 2. Clean up CatalogTracker. waitForMeta waits for "timeout" value. When
waitForMetaServerConnectionDefault is called by MetaNodeTracker, the timeout
value is large. So it doesn't retry in case .ROOT. is updated; add the proper
implementation for CatalogTracker.verifyMetaRegionLocation
bq. 4. Check for the latest -ROOT- and .META. region location during the
handling of server shutdown.
bq. 5. Right after assigning the -ROOT- or .META. in ServerShutdownHandler,
don't block and wait for .META. availability. Resubmit another
ServerShutdownHandler for regular regions.
bq.
bq.
bq. This addresses bug HBASE-4455.
bq. https://issues.apache.org/jira/browse/HBASE-4455
bq.
bq.
bq. Diffs
bq. -----
bq.
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/zookeeper/RootRegionTracker.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperNodeTracker.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/test/java/org/apache/hadoop/hbase/zookeeper/TestZooKeeperNodeTracker.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/handler/OpenRegionHandler.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/zookeeper/ClusterStatusTracker.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/handler/CloseRegionHandler.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/handler/MetaServerShutdownHandler.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/handler/OpenedRegionHandler.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/handler/ServerShutdownHandler.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/ServerManager.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/MasterAddressTracker.java
1172205
bq.
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/catalog/CatalogTracker.java
1172205
bq.
bq. Diff: https://reviews.apache.org/r/2007/diff
bq.
bq.
bq. Testing
bq. -------
bq.
bq. Keep Master up all the time, do rolling restart of RSs like this - stop
RS1, wait for 2 seconds, stop RS2, start RS1, wait for 2 seconds, stop RS3,
start RS2, wait for 2 seconds, etc. The program can run for couple hours until
it stops. -ROOT- and .META. are available during that time.
bq.
bq.
bq. Thanks,
bq.
bq. Ming
bq.
bq.
> Rolling restart RSs scenario, -ROOT-, .META. regions are lost in
> AssignmentManager
> ----------------------------------------------------------------------------------
>
> Key: HBASE-4455
> URL: https://issues.apache.org/jira/browse/HBASE-4455
> Project: HBase
> Issue Type: Bug
> Reporter: Ming Ma
> Assignee: Ming Ma
> Fix For: 0.92.0
>
>
> Keep Master up all the time, do rolling restart of RSs like this - stop RS1,
> wait for 2 seconds, stop RS2, start RS1, wait for 2 seconds, stop RS3, start
> RS2, wait for 2 seconds, etc. After a while, you will find the -ROOT-, .META.
> regions aren't in "regions in transtion" from AssignmentManager point of
> view, but they aren't assigned to any regions. Here are the issues.
> 1. .-ROOT- or .META. location is stale when MetaServerShutdownHandler is
> invoked to check if it contains -ROOT- region. That is due to long delay from
> ZK notification and async nature of the system. Here is an example, even
> though new root region server sea-lab-1,60020,1316380133656 is set at T2, at
> T3 the shutdown process for sea-lab-1,60020,1316380133656, the root location
> still points to old server sea-lab-3,60020,1316380037898.
> T1: 2011-09-18 14:08:52,470 DEBUG org.apache.hadoop.hbase.zookeeper.ZKUtil:
> master:6
> 0000-0x1327e43175e0000 Retrieved 29 byte(s) of data from znode
> /hbase/root-regio
> n-server and set watcher; sea-lab-3,60020,1316380037898
> T2: 2011-09-18 14:08:57,173 INFO
> org.apache.hadoop.hbase.catalog.RootLocationEditor: Setting ROOT region
> location in ZooKeeper as sea-lab-1,60020,1316380133656
> T3: 2011-09-18 14:10:26,393 DEBUG
> org.apache.hadoop.hbase.master.ServerManager: Adde
> d=sea-lab-1,60020,1316380133656 to dead servers, submitted shutdown handler
> to be executed, root=false, meta=true, current Root Location:
> sea-lab-3,60020,1316380037898
> T4: 2011-09-18 14:12:37,314 DEBUG org.apache.hadoop.hbase.zookeeper.ZKUtil:
> master:6
> 0000-0x1327e43175e0000 Retrieved 29 byte(s) of data from znode
> /hbase/root-region-server and set watcher; sea-lab-1,60020,1316380133656
> 2. The MetaServerShutdownHandler worker thread that waits for -ROOT- or
> .META. availability could be blocked. If meanwhile, the new server that
> -ROOT- or .META. is being assigned restarted, another instance of
> MetaServerShutdownHandler is queued. Eventually, all
> MetaServerShutdownHandler worker threads are filled up. It looks like
> HBASE-4245.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
