That is correct. Also, disabling a table requires scanning and modifying the .META. region so if it happens to be slow then that operation will be slow too.
J-D On Tue, Mar 1, 2011 at 10:55 AM, Nanheng Wu <[email protected]> wrote: > I see, so the Get only gets affected on regions not in client's cache. > I think that explains why that error seems hard to reproduce. This is > how I understood a Get works: if the client doesn't have the region in > its cache it will read .META. table; and if it does it makes a RPC to > the RS directly; also each RS has some data about the regions it > actually hosts, so if the region is not there it means the client's > cache is stale and the client has to read the .META. again. Is this > correct? > > On Tue, Mar 1, 2011 at 10:48 AM, Jean-Daniel Cryans <[email protected]> > wrote: >> Depends if you have to query .META. first to get the location of the >> region that hosts the row. >> >> J-D >> >> On Tue, Mar 1, 2011 at 10:45 AM, Nanheng Wu <[email protected]> wrote: >>> Man I appreciate so much all the help you provided so far. I guess >>> I'll keep digging. Would this meta scan cause Get or Scan on user >>> tables to be very very slow too? That was actually was the problem I >>> first noticed: from time to time a client Get or Scan would be >>> extremely slow on my tables. >>> >>> On Tue, Mar 1, 2011 at 10:38 AM, Jean-Daniel Cryans <[email protected]> >>> wrote: >>>> The store file looks fairly new, maybe it was just major compacted? >>>> You could easily figure that out from the region server's log. >>>> >>>> Your problem is definitely a .META. region slowness. If scanning 8k >>>> rows takes 30 minutes, scanning and updating 260 rows at the same time >>>> probably isn't much faster. >>>> >>>> J-D >>>> >>>> On Tue, Mar 1, 2011 at 10:34 AM, Nanheng Wu <[email protected]> wrote: >>>>> J-D, >>>>> >>>>> It looks like I don't have that many files: >>>>> >>>>> drwxr-xr-x - root supergroup 0 2011-02-28 23:21 >>>>> /hbase/.META./1028785192 >>>>> -rw-r--r-- 3 root supergroup 932 2011-02-03 19:23 >>>>> /hbase/.META./1028785192/.regioninfo >>>>> drwxr-xr-x - root supergroup 0 2011-03-01 17:13 >>>>> /hbase/.META./1028785192/info >>>>> -rw-r--r-- 3 root supergroup 11831330 2011-03-01 17:13 >>>>> /hbase/.META./1028785192/info/6687606720393313750 >>>>> drwxr-xr-x - root supergroup 0 2011-03-01 17:13 >>>>> /hbase/.META./compaction.dir >>>>> >>>>> So you think compaction on .META. table on the RS could be the >>>>> problem? while the log metaScanner is running I saw virtually no logs >>>>> on that server though, I did see compactions once the meta scan ended >>>>> and region close started to happen. I wonder what the cluster is doing >>>>> while the meta scan is going. >>>>> >>>>> I would definitely upgrade in the near future, it's just that I am >>>>> afraid upgrading won't guarantee a fix if I don't understand the >>>>> nature of the problem more clearly. We also have another test cluster, >>>>> running the same versions of everything on cheaper hardware and it >>>>> doesn't have this problem. >>>>> >>>>> On Tue, Mar 1, 2011 at 9:52 AM, Jean-Daniel Cryans <[email protected]> >>>>> wrote: >>>>>> That long .META. scan might be the culprit, good catch! >>>>>> >>>>>> If you run this from the hadoop folder: >>>>>> >>>>>> bin/hadoop dfs -lsr /hbase/.META. >>>>>> >>>>>> Do you see a ton of files? Let's define "ton" as more than 16 files. >>>>>> If so, and I see you have a very high number of regions, then you >>>>>> could be hitting this problem: >>>>>> https://issues.apache.org/jira/browse/HBASE-3499 >>>>>> >>>>>> In short, every few .META. change will result in a flush and it could >>>>>> be that the region server hosting it isn't able to keep up with the >>>>>> compactions. It's done so that since append isn't supported in your >>>>>> hadoop that you won't lose too much data if the node dies, which is >>>>>> really bad when it happens to .META. >>>>>> >>>>>> In your case it might not be so bad to set your .META.'s MEMSTORE_SIZE >>>>>> back to the default value if you're not writing hence not splitting. >>>>>> Running the script attached in that jira would do it (don't forget to >>>>>> restart HBase after running it). >>>>>> >>>>>> Lastly, upgrading to HBase 0.90.1 and a hadoop that supports append >>>>>> should be a priority. >>>>>> >>>>>> J-D >>>>>> >>>>>> On Tue, Mar 1, 2011 at 9:30 AM, Nanheng Wu <[email protected]> wrote: >>>>>>> Hi J-D: >>>>>>> >>>>>>> I did the scan like you suggested but no splits came up. This kind >>>>>>> of makes sense to me, since we write Hfiles using a MR job and then >>>>>>> pretty much use HBase for read-only so maybe that's why the regions >>>>>>> never got split? I think my slow disable problem is related to this >>>>>>> RegionManager.metaScanner. I greped for that in the Masters log and I >>>>>>> saw: >>>>>>> 11/03/01 15:30:37 INFO master.BaseScanner: RegionManager.metaScanner >>>>>>> scanning meta region {server: 10.146.14.38:60020, regionname: >>>>>>> .META.,,1, startKey: <>} >>>>>>> 11/03/01 15:55:40 INFO master.BaseScanner: RegionManager.metaScanner >>>>>>> scan of 8296 row(s) of meta region {server: 10.146.14.38:60020, >>>>>>> regionname: .META.,,1, startKey: <>} complete >>>>>>> 11/03/01 15:55:40 INFO master.BaseScanner: RegionManager.metaScanner >>>>>>> scanning meta region {server: 10.146.14.38:60020, regionname: >>>>>>> .META.,,1, startKey: <>} >>>>>>> Thread 27 (RegionManager.metaScanner): >>>>>>> 11/03/01 16:21:04 INFO master.BaseScanner: RegionManager.metaScanner >>>>>>> scan of 8296 row(s) of meta region {server: 10.146.14.38:60020, >>>>>>> regionname: .META.,,1, startKey: <>} complete >>>>>>> 11/03/01 16:21:04 INFO master.BaseScanner: RegionManager.metaScanner >>>>>>> scanning meta region {server: 10.146.14.38:60020, regionname: >>>>>>> .META.,,1, startKey: <>} >>>>>>> Thread 27 (RegionManager.metaScanner): >>>>>>> 11/03/01 16:46:07 INFO master.BaseScanner: RegionManager.metaScanner >>>>>>> scan of 8298 row(s) of meta region {server: 10.146.14.38:60020, >>>>>>> regionname: .META.,,1, startKey: <>} complete >>>>>>> >>>>>>> It looks like meta scanner is always running, each time taking 20-30 >>>>>>> minutes. Here's what I did: >>>>>>> >>>>>>> 1) disable table -> at 16:28:31, according the log above there's a >>>>>>> meta scan in progress. >>>>>>> >>>>>>> 2 ) the command hangs, no output in .META RS's log >>>>>>> at 11/03/01 16:46:57 the client got 11/03/01 16:46:58 DEBUG >>>>>>> zookeeper.ZooKeeperWrapper: Read ZNode /hbase/root-region-server got >>>>>>> 10.146.14.38:60020 >>>>>>> 11/03/01 16:46:58 DEBUG client.HConnectionManager$TableServers: Found >>>>>>> ROOT at 10.146.14.38:60020 >>>>>>> 11/03/01 16:46:58 DEBUG client.HConnectionManager$TableServers: Cached >>>>>>> location for .META.,,1 is 10.146.14.38:60020 >>>>>>> This corresponds exact to when the meta scan completed. .META RS >>>>>>> started to spew some logs about closing regions. >>>>>>> >>>>>>> 3) Another meta scan started and the client hangs again until it >>>>>>> finishes, and disable command returns.The whole thing took 2688.5930 >>>>>>> seconds >>>>>>> >>>>>>> What kind of problem does it look like to you J-D? What does this >>>>>>> background task metaScanner do? >>>>>>> >>>>>>> Thanks! >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Mon, Feb 28, 2011 at 5:17 PM, Jean-Daniel Cryans >>>>>>> <[email protected]> wrote: >>>>>>>> I didn't get most of the information I was looking for... but I do >>>>>>>> have something to work with. So I asked whether the metaScanner was >>>>>>>> making progress or not, and from that log I think I see it does: >>>>>>>> >>>>>>>>> 11/03/01 00:47:30 DEBUG client.HConnectionManager$TableServers: >>>>>>>>> Rowscanned=261, rowsOffline=3 >>>>>>>>> 11/03/01 00:47:30 DEBUG client.HBaseAdmin: Sleep. Waiting for all >>>>>>>>> regions to be disabled from myTable >>>>>>>> >>>>>>>> Only 3 rows are offline, whereas we expect all the region to be >>>>>>>> offline. I expect you see those lines a lot? If so, one thing I'd like >>>>>>>> to see is the result of this command: >>>>>>>> >>>>>>>> scan '.META.', {STARTROW => "myTable,,", LIMIT => 261} >>>>>>>> >>>>>>>> It's going to be big. Then grep in the result for the string SPLIT, >>>>>>>> and please post back here the lines that match. >>>>>>>> >>>>>>>> J-D >>>>>>>> >>>>>>>> On Mon, Feb 28, 2011 at 5:04 PM, Nanheng Wu <[email protected]> >>>>>>>> wrote: >>>>>>>>> I issued two more disable commands and looked at the .META RS. The >>>>>>>>> last log entry looks like: >>>>>>>>> >>>>>>>>> 11/03/01 00:29:14 INFO regionserver.HLog: Roll >>>>>>>>> /hbase/.logs/<RS_HOSTNAME>,60020,1298935751670/hlog >>>>>>>>> .dat.1298935752660, entries=13527, calcsize=3839046, filesize=2560143. >>>>>>>>> New hlog >>>>>>>>> /hbase/.logs/<RS_HOSTNAME>,60020,1298935751670/hlog.dat.1298939354072 >>>>>>>>> >>>>>>>>> I issued the command at: 00:34:59, the client debug message has >>>>>>>>> nothing but "11/03/01 00:34:59 DEBUG zookeeper.ClientCnxn: Got ping >>>>>>>>> response for sessionid:0x12e6e938e9c000b after 90ms" until 00:47:19. >>>>>>>>> Then all of a sudden it outputs the following: >>>>>>>>> >>>>>>>>> 0:47:28 DEBUG client.HConnectionManager$TableServers: Cache hit for >>>>>>>>> row <> in tableName .META.: location server 10.146.14.38:60020, >>>>>>>>> location region name .META.,,1 >>>>>>>>> 11/03/01 00:47:28 DEBUG zookeeper.ZooKeeperWrapper: Read ZNode >>>>>>>>> /hbase/root-region-server got 10.146.14.38:60020 >>>>>>>>> 11/03/01 00:47:28 DEBUG client.HConnectionManager$TableServers: Found >>>>>>>>> ROOT at 10.146.14.38:60020 >>>>>>>>> 11/03/01 00:47:28 DEBUG client.HConnectionManager$TableServers: Cached >>>>>>>>> location for .META.,,1 is 10.146.14.38:60020 >>>>>>>>> 11/03/01 00:47:30 DEBUG client.HConnectionManager$TableServers: >>>>>>>>> Rowscanned=261, rowsOffline=3 >>>>>>>>> 11/03/01 00:47:30 DEBUG client.HBaseAdmin: Sleep. Waiting for all >>>>>>>>> regions to be disabled from myTable >>>>>>>>> 11/03/01 00:47:31 DEBUG client.HBaseAdmin: Wake. Waiting for all >>>>>>>>> regions to be disabled from myTable >>>>>>>>> >>>>>>>>> Here's the full thread dump of the .META RS from 00:34:59 to 00:47:31 >>>>>>>>> http://pastebin.com/Ywwx8afQ >>>>>>>>> >>>>>>>>> I hope I compiled some useful information here. I am pretty lost at >>>>>>>>> this point, I would really appreciate your help! >>>>>>>>> >>>>>>>>> Thanks! >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> On Mon, Feb 28, 2011 at 2:58 PM, Jean-Daniel Cryans >>>>>>>>> <[email protected]> wrote: >>>>>>>>>> Ok so no debug from the disable command? BTW you should output your >>>>>>>>>> GC >>>>>>>>>> somewhere else like the .out file or a completely separate file. >>>>>>>>>> >>>>>>>>>> J-D >>>>>>>>>> >>>>>>>>>> On Mon, Feb 28, 2011 at 2:54 PM, Nanheng Wu <[email protected]> >>>>>>>>>> wrote: >>>>>>>>>>> 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. >>>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> >> >
