This jute buffer len error generally means a given znode being watched/read had grown too large to fit into the buffer. It's not specific to number of watches attached, but amount of info stored in it, for example, too many children znode under a given znode. In order to understand what's behind the error, you should analyse your zookeeper znodes tree, you may have a hint by looking at zookeeper snapashot files. Would you have replication enabled on this cluster? A common cause for such errors in hbase is when replication is slow/stuck, and source cluster is under heavy write load, causing replication queue to grow much faster than it's ability to drain, which will imply on many znodes created under "replication" znode.
Em seg, 11 de mar de 2019 às 04:58, Asim Zafir <[email protected]> escreveu: > Hi Stack, > We are seeing excessive Region Server exists along with ZK connection tear > down (Len error, jute buffer threshold being reached) > I want to see what is contributing jute buffer reaching the max upper > bound. so for after investigating the code and studying the protocol itself > it appear it is a function of number of watches that gets set on the > znodes. to bring stability to ZK service, we had to increase jute.buffer > from 1mb to 20mb, 32mb and now it is set to 128mb. In order to understand > more, I digged little bit more to see how many zookeeper watch objects are > on zookeeper jvm /instance. I did a jmap history:live on zookeeper pid and > I got the following output (please see below). I am not sure what is [C, [B > here and it doesn't appear its refers to any class - I don't see this on > dev instance of zookeeper. due to suspect memory leak or another issue? > Please guide me through this as I can't find a resource who can go that far > to give me any hint as to what may be happening on my end. Also is it safe > for ZK sizes to increase that much? what is the impact of jute-buffer > increasing on hbase? I will greatly appreciate your feedback and help on > this. > > num #instances #bytes class name > > ---------------------------------------------- > > 1: 220810 140582448 [C > > 2: 109370 34857168 [B > > 3: 103842 7476624 org.apache.zookeeper.data.StatPersisted > > 4: 220703 5296872 java.lang.String > > 5: 28682 3783712 <constMethodKlass> > > 6: 28682 3681168 <methodKlass> > > 7: 111000 3552000 java.util.HashMap$Entry > > 8: 107569 3442208 > java.util.concurrent.ConcurrentHashMap$HashEntry > > 9: 103842 3322944 org.apache.zookeeper.server.DataNode > > 10: 2655 3179640 <constantPoolKlass> > > 11: 2313 2017056 <constantPoolCacheKlass> > > 12: 2655 1842456 <instanceKlassKlass> > > 13: 318 1241568 > [Ljava.util.concurrent.ConcurrentHashMap$HashEntry; > > 14: 7526 1221504 [Ljava.util.HashMap$Entry; > > 15: 1820 812976 <methodDataKlass> > > 16: 8228 394944 java.util.HashMap > > 17: 2903 348432 java.lang.Class > > 18: 4077 229688 [S > > 19: 4138 221848 [[I > > 20: 231 125664 <objArrayKlassKlass> > > 21: 7796 124736 java.util.HashSet > > 22: 6771 108336 java.util.HashMap$KeySet > > 23: 1263 62968 [Ljava.lang.Object; > > 24: 746 59680 java.lang.reflect.Method > > 25: 3570 57120 java.lang.Object > > 26: 502 36144 org.apache.zookeeper.server.Request > > 27: 649 25960 java.lang.ref.SoftReference > > 28: 501 24048 org.apache.zookeeper.txn.TxnHeader > > 29: 188 21704 [I > > 30: 861 20664 java.lang.Long > > 31: 276 19872 java.lang.reflect.Constructor > > 32: 559 17888 > java.util.concurrent.locks.ReentrantLock$NonfairSync > > 33: 422 16880 java.util.LinkedHashMap$Entry > > 34: 502 16064 > org.apache.zookeeper.server.quorum.QuorumPacket > > 35: 455 14560 java.util.Hashtable$Entry > > 36: 495 14368 [Ljava.lang.String; > > 37: 318 12720 > java.util.concurrent.ConcurrentHashMap$Segment > > 38: 3 12336 [Ljava.nio.ByteBuffer; > > 39: 514 12336 javax.management.ObjectName$Property > > 40: 505 12120 java.util.LinkedList$Node > > 41: 501 12024 > org.apache.zookeeper.server.quorum.Leader$Proposal > > 42: 619 11920 [Ljava.lang.Class; > > 43: 74 11840 > org.apache.zookeeper.server.NIOServerCnxn > > 44: 145 11672 [Ljava.util.Hashtable$Entry; > > 45: 729 11664 java.lang.Integer > > 46: 346 11072 java.lang.ref.WeakReference > > 47: 449 10776 org.apache.zookeeper.txn.SetDataTxn > > 48: 156 9984 > com.cloudera.cmf.event.shaded.org.apache.avro.Schema$Props > > 49: 266 8512 java.util.Vector > > 50: 75 8400 sun.nio.ch.SocketChannelImpl > > 51: 175 8400 java.nio.HeapByteBuffer > > 52: 247 8320 [Ljavax.management.ObjectName$Property; > > 53: 303 7272 com.cloudera.cmf.event.EventCode > > 54: 300 7200 java.util.ArrayList > > 55: 136 6528 java.util.Hashtable > > 56: 156 6240 java.util.WeakHashMap$Entry > > 57: 194 6208 > com.sun.jmx.mbeanserver.ConvertingMethod >
