I see, so I should jstack the .META region. I'll do that. The master log pretty much looks like this: should I grep for something specific?
11/02/28 22:52:56 INFO master.BaseScanner: RegionManager.rootScanner scan of 1 row(s) of meta region complete 2011-02-28T22:52:57.138+0000: 263241.014: [GC 263241.014: [ParNew: 19136K->2112K(19136K), 0.0033350 secs] 378606K->36159 6K(641944K) icms_dc=0 , 0.0034330 secs] [Times: user=0.02 sys=0.00, real=0.00 secs] 2011-02-28T22:53:04.956+0000: 263248.832: [GC 263248.832: [ParNew: 19068K->2112K(19136K), 0.0029690 secs] 378552K->36163 0K(641944K) icms_dc=0 , 0.0030460 secs] [Times: user=0.02 sys=0.00, real=0.00 secs] 2011-02-28T22:53:12.664+0000: 263256.540: [GC 263256.541: [ParNew: 19136K->2112K(19136K), 0.0037690 secs] 378654K->36164 7K(641944K) icms_dc=0 , 0.0038660 secs] [Times: user=0.01 sys=0.00, real=0.01 secs] 2011-02-28T22:53:20.608+0000: 263264.484: [GC 263264.484: [ParNew: 19136K->1810K(19136K), 0.0032600 secs] 378671K->36134 6K(641944K) icms_dc=0 , 0.0033470 secs] [Times: user=0.02 sys=0.00, real=0.01 secs] 2011-02-28T22:53:28.278+0000: 263272.154: [GC 263272.154: [ParNew: 18834K->2112K(19136K), 0.0029870 secs] 378370K->36166 1K(641944K) icms_dc=0 , 0.0030670 secs] [Times: user=0.01 sys=0.00, real=0.01 secs] 2011-02-28T22:53:35.919+0000: 263279.795: [GC 263279.795: [ParNew: 19136K->1747K(19136K), 0.0037090 secs] 378685K->36129 8K(641944K) icms_dc=0 , 0.0037920 secs] [Times: user=0.02 sys=0.00, real=0.01 secs] 11/02/28 22:53:36 INFO master.ServerManager: 9 region servers, 0 dead, average load 760.2222222222222 On Mon, Feb 28, 2011 at 2:49 PM, Jean-Daniel Cryans <[email protected]> wrote: > Are you able to tell if that call in metaScanner is hanging or it's > making multiple calls to the .META. region? > > If former, then jstack the region server that hosts .META. and see > where it's blocked. > > if latter, then it means your .META. region is slow? Again, what's > going on on the RS that hosts .META.? > > Finally, what's the master's log like during that time? > > J-D > > On Mon, Feb 28, 2011 at 2:41 PM, Nanheng Wu <[email protected]> wrote: >> J-D, >> >> Thanks so much for your help so far! I sent disable commands on 4 >> rather small tables and they got stuck for a long time again, so I >> took jstack of the master. From what I can tell, all disableTable >> calls are blocked by a meta scanner thread (sample log below). At the >> moment there were no other requests to the server at all. How should I >> investigate this further? If it helps, here's some background: I have >> several datasets, each of them is in a separate table; Our data >> pipeline produces a new version of each dataset everyday and only the >> lastest version should be used. This is how the data is loaded: for >> each dataset 1) run a MR job and outputs HFiles 2) call loadTable.rb >> to create a new table 3) disable and drop the previous version. As a >> result some calls to load table and drop table would overlap. Please >> let me know if something stands out to you as a potential culprit. >> Thanks! >> >> BTW, I am running Hadoop 0.20.2 with HBase 0.20.6 >> >> Thread 47 (IPC Server handler 13 on 60000): >> State: BLOCKED >> Blocked count: 3801 >> Waited count: 72719 >> Blocked on java.lang.Object@75ac522c >> Blocked by 27 (RegionManager.metaScanner) >> Stack: >> >> org.apache.hadoop.hbase.master.TableOperation.process(TableOperation.java:154) >> org.apache.hadoop.hbase.master.HMaster.disableTable(HMaster.java:842) >> sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source) >> >> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) >> java.lang.reflect.Method.invoke(Method.java:597) >> org.apache.hadoop.hbase.ipc.HBaseRPC$Server.call(HBaseRPC.java:657) >> org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:915) >> >> >> Thread 27 (RegionManager.metaScanner): >> State: WAITING >> Blocked count: 1526058 >> Waited count: 1488998 >> Waiting on org.apache.hadoop.hbase.ipc.HBaseClient$Call@4dd44ab0 >> Stack: >> java.lang.Object.wait(Native Method) >> java.lang.Object.wait(Object.java:485) >> org.apache.hadoop.hbase.ipc.HBaseClient.call(HBaseClient.java:722) >> org.apache.hadoop.hbase.ipc.HBaseRPC$Invoker.invoke(HBaseRPC.java:333) >> $Proxy1.get(Unknown Source) >> >> org.apache.hadoop.hbase.master.BaseScanner.checkAssigned(BaseScanner.java:543) >> >> org.apache.hadoop.hbase.master.BaseScanner.scanRegion(BaseScanner.java:192) >> >> org.apache.hadoop.hbase.master.MetaScanner.scanOneMetaRegion(MetaScanner.java:73) >> >> org.apache.hadoop.hbase.master.MetaScanner.maintenanceScan(MetaScanner.java:129) >> org.apache.hadoop.hbase.master.BaseScanner.chore(BaseScanner.java:153) >> org.apache.hadoop.hbase.Chore.run(Chore.java:68) >> >> >> >> >> On Fri, Feb 25, 2011 at 10:23 AM, Jean-Daniel Cryans >> <[email protected]> wrote: >>> An hour to disable? That doesn't sound right at all :) >>> >>> I would approach this problem like I generally do with HBase issue, >>> first check the master log for any weirdness regarding my problem (in >>> this case, grep for the table name). >>> >>> Then I would look the region server log(s) of the nodes that were >>> hosting regions from that table. You should see the steps taken to >>> disable the regions (starting to close, flush, region completely >>> closed). >>> >>> If you are able to do it while it's taking a very long time to >>> disable, try to jstack the process the seems to be hanging. >>> >>> Finally, like I said in another thread, there's a bug in 0.20.6 that >>> almost prevent disabling a table (or re-enabling) if any region >>> recently split and the parent wasn't cleaned yet from .META. and that >>> is fixed in 0.90.1 >>> >>> J-D >>> >>> On Thu, Feb 24, 2011 at 11:37 PM, Nanheng Wu <[email protected]> wrote: >>>> I think you are right, maybe in the long run I need to re-architect my >>>> system so that it doesn't need to create new and delete old tables all >>>> the time. In the short term I am having a really hard time with the >>>> disabling function, I ran a disable command on a very small table >>>> (probably dozen of MBs in size) and are no client using the cluster at >>>> all, and that took about 1 hour to complete! The weird thing is on the >>>> web UI only the region server carrying the META table has non-zero >>>> requests, all other RS have 0 requests the entire time. I would think >>>> they should get some request to flush the memstore at least. I *am* >>>> using the same RS nodes for some map reduce job at the time and top >>>> shows the memory usage is almost full on the META region. Would you >>>> have some idea of what I should investigate? >>>> Thanks so much. >>> >> >
