Thanks. I think that gc resulted in It is difficult to reproduce. I find it firstly in performance test cluster.
-----邮件原件----- 发件人: Ted Yu [mailto:yuzhih...@gmail.com] 发送时间: 2011年5月11日 10:31 收件人: user@hbase.apache.org 主题: Re: A question about client I think the second explanation is plausible. From http://download.oracle.com/javase/1.4.2/docs/api/java/lang/ref/SoftReference.html : Soft reference objects, which are cleared at the discretion of the garbage collector in response to memory demand. I think we should check whether possibleRegion is null in the code below. 2011/5/10 Jean-Daniel Cryans <jdcry...@apache.org> > Are you running a modified YCSB by any chance? Because last time I > looked at that code it didn't share the HTables between threads and it > looks like it's doing something like that. > > Looking more deeper at the code, the NoSuchElementException is thrown > because the map is empty. This is what that code looks like: > > if (!matchingRegions.isEmpty()) { > HRegionLocation possibleRegion = > matchingRegions.get(matchingRegions.lastKey()); > > So to me it seems that the only way you would get this exception is if > someone emptied the map between the isEmpty call and lastKey which > shouldn't happen if HTables aren't shared. > > The only other way it seems it could happen, and it's a stretch, is > that since the regions are kept in a SoftValueSortedMap then the GC > would have removed the elements you needed exactly between those two > lines... Is it easy for you to recreate the issue? > > Thx a bunch, > > J-D > > On Mon, May 9, 2011 at 11:34 PM, Gaojinchao <gaojinc...@huawei.com> wrote: > > Hbase version: 0.90.2 . > > I merged patches: > > HBASE-3773 Set ZK max connections much higher in 0.90 > > HBASE-3771 All jsp pages don't clean their HBA > > HBASE-3783 hbase-0.90.2.jar exists in hbase root and in 'lib/' > > HBASE-3756 Can't move META or ROOT from shell > > HBASE-3744 createTable blocks until all regions are out of > transition > > HBASE-3712 HTable.close() doesn't shutdown thread pool > > HBASE-3750 HTablePool.putTable() should call > tableFactory.releaseHTableInterface() for discarded table > > HBASE-3722 A lot of data is lost when name node crashed > > HBASE-3800 If HMaster is started after NN without starting DN in > Hbase 090.2 then HMaster is not able to start due to AlreadyCreatedException > for /hbase/hbase.version > > HBASE-3749 Master can't exit when open port failed > > > > -----邮件原件----- > > 发件人: jdcry...@gmail.com [mailto:jdcry...@gmail.com] 代表 Jean-Daniel > Cryans > > 发送时间: 2011年5月10日 1:17 > > 收件人: user@hbase.apache.org > > 主题: Re: A question about client > > > > TreeMap isn't concurrent and it seems it was used that way? I know you > > guys are testing a bunch of different things at the same time so which > > HBase version and which patches were you using when you got that? > > > > Thx, > > > > J-D > > > > On Mon, May 9, 2011 at 5:22 AM, Gaojinchao <gaojinc...@huawei.com> > wrote: > >> I used ycsb to put data and threw exception. > >> Who can give me some suggestion? > >> > >> Hbase Code: > >> // Cut the cache so that we only get the part that could contain > >> // regions that match our key > >> SoftValueSortedMap<byte[], HRegionLocation> matchingRegions = > >> tableLocations.headMap(row); > >> > >> // if that portion of the map is empty, then we're done. otherwise, > >> // we need to examine the cached location to verify that it is > >> // a match by end key as well. > >> if (!matchingRegions.isEmpty()) { > >> HRegionLocation possibleRegion = > >> matchingRegions.get(matchingRegions.lastKey()); > >> > >> ycsb client log: > >> > >> [java] begin StatusThread run > >> [java] java.util.NoSuchElementException > >> [java] at java.util.TreeMap.key(TreeMap.java:1206) > >> [java] at > java.util.TreeMap$NavigableSubMap.lastKey(TreeMap.java:1435) > >> [java] at > org.apache.hadoop.hbase.util.SoftValueSortedMap.lastKey(SoftValueSortedMap.java:131) > >> [java] at > org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getCachedLocation(HConnectionManager.java:841) > >> [java] at > org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegionInMeta(HConnectionManager.java:664) > >> [java] at > org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:590) > >> [java] at > org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.processBatch(HConnectionManager.java:1114) > >> [java] at > org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.processBatchOfPuts(HConnectionManager.java:1234) > >> [java] at > org.apache.hadoop.hbase.client.HTable.flushCommits(HTable.java:819) > >> [java] at > org.apache.hadoop.hbase.client.HTable.doPut(HTable.java:675) > >> [java] at > org.apache.hadoop.hbase.client.HTable.put(HTable.java:665) > >> [java] at com.yahoo.ycsb.db.HBaseClient.update(Unknown Source) > >> [java] at com.yahoo.ycsb.db.HBaseClient.insert(Unknown Source) > >> [java] at com.yahoo.ycsb.DBWrapper.insert(Unknown Source) > >> [java] at com.yahoo.ycsb.workloads.MyWorkload.doInsert(Unknown > Source) > >> [java] at com.yahoo.ycsb.ClientThread.run(Unknown Source) > >> > > >
