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From Serega Sheypak <serega.shey...@gmail.com>
Subject Re: HConnectionManager leaks with zookeeper conection oo many connections from /my.tomcat.server.com - max is 60
Date Sat, 13 Dec 2014 13:13:31 GMT
Hm... confusing,
So here is the code path:
1. Servlet has doPost method
2. HistoryController instantiated during each doPost request.
HistoryController is Logic wrapper around low-level HBase persistence stuff
Each doPost invokes:


final HistoryController getHistoryController(){
    return new HistoryController(configuration: getHBaseConfiguration())
}

getHistoryController().updateHistory(historyEntryVisitorId)

3. HistoryController has method:

private HistoryEntryConnection getConnection(){
    new HistoryEntryConnection(configuration)
}


so each

updateHistory(historyEntryVisitorId)


gets new low-level HistoryEntryConnection

instance.

HistoryEntryConnection is dead simple, I've shown it previously

public void put(List<MyBean> entries){
    HConnection hConnection = null;
    HTableInterface hTable = null;
    try {
        List<Put> puts = new ArrayList<Put>(entries.size());
        for(MyBean myBean : entries){
            puts.add(new MyBeanSerDe().createPut(myBean));
        }
        hConnection = HConnectionManager.createConnection(configuration);
        hTable = hConnection.getTable(NAME_B);
        hTable.put(puts);

    }catch (Exception e){
        LOG.error("Error while doing bulk put", e);
    }finally{
        close(hTable);
        close(hConnection);
    }
}


Manager, Connection, HTable usage copy-pasted from javadoc. Nothing new.
BTW, is there any possibility to limit quantity of opened connections in
HConnectionManager internals ?
I have several web-apps using HBase as backends. Maybe their cumulative
pressure makes ZK go down...


2014-12-13 4:03 GMT+03:00 Stack <stack@duboce.net>:
>
> On Fri, Dec 12, 2014 at 11:45 AM, Serega Sheypak <serega.sheypak@gmail.com
> >
> wrote:
> >
> > i have 10K doPost/doGet requests per second.
> >
>
> How many concurrent threads going on in your tomcat?  Is the Connection
> shared amongst all threads?  Perhaps you have > 60 concurrent connections
> running at a time and each Connection has its own zk instance.  Thread
> dump?
>
> Post all the code?
>
> I tried multithreaded with 100 threads but still can't repro (see code
> below).  Next would be to get zk to dump concurrent connection count but
> lets see what your answers above are first.
>
> St.Ack
>
>
> public class TestConnnection {
>
>   static class Putter extends Thread {
>
>     Configuration c;
>
>     Putter(final Configuration c, final String i) {
>
>       super(i);
>
>       this.c = c;
>
>     }
>
>
>     @Override
>
>     public void run() {
>
>       try {
>
>       for (int i = 0; i < 100; i++) {
>
>         HConnection connection = HConnectionManager.createConnection(this.c
> );
>
>         HTableInterface table = connection.getTable(TableName.valueOf(
> "table1"));
>
>         byte [] cf = Bytes.toBytes("t");
>
>         try {
>
>           byte [] bytes = Bytes.toBytes(i);
>
>           Put p = new Put(bytes);
>
>           p.add(cf, cf, bytes);
>
>           table.put(p);
>
>         } finally {
>
>           table.close();
>
>           connection.close();
>
>         }
>
>         System.out.println(getName() + ", i=" + i);
>
>       }
>
>       } catch (Throwable t) {
>
>         throw new RuntimeException(t);
>
>       }
>
>     }
>
>   };
>
>
>   public static void main(String[] args) throws IOException {
>
>     Configuration config = HBaseConfiguration.create();
>
>     for (int i = 0; i < 100; i++) {
>
>       Thread t = new Putter(config, "" + i);
>
>       t.start();
>
>     }
>
>   }
>
> }
>
>
>
>
>
> > Servlet is NOT single-threaded. each doPost/doGet
> > invokes these lines (encapsulated in DAO):
> >
> >  16       HConnection connection =
> > HConnectionManager.createConnection(config);
> >  17       HTableInterface table =
> > connection.getTable(TableName.valueOf("table1"));
> >
> > and
> >
> > 24       } finally {
> >  25         table.close();
> >  26         connection.close();
> >  27       }
> >
> > I assumed that this static construction
> >
> > 16       HConnection connection =
> > HConnectionManager.createConnection(config);
> >
> > correctly handles multi-threaded access somewhere deep inside.
> > Right now I don't understand what do I do wrong.
> >
> > Try to wrap each your request in Runnable to emulate multi-threaded
> > pressure on ZK. Your code is linear and mine is not, it's concurrent.
> >
> > Thanks....
> >
> >
> >
> >
> > 2014-12-12 22:28 GMT+03:00 Stack <stack@duboce.net>:
> > >
> > > I cannot reproduce. I stood up a cdh5.2 server and then copy/pasted
> your
> > > code adding in a put for each cycle.  I ran loop 1000 times and no
> > > complaint from zk.
> > >
> > > Tell me more (Is servlet doing single-threaded model?  A single
> > > Configuration is being used or new ones are being created per servlet
> > > invocation?
> > >
> > > Below is code and output.
> > >
> > > (For better perf, cache the connection)
> > > St.Ack
> > >
> > >
> > >   1 package org.apache.hadoop.hbase;
> > >   2
> > >   3 import java.io.IOException;
> > >   4
> > >   5 import org.apache.hadoop.conf.Configuration;
> > >   6 import org.apache.hadoop.hbase.client.HConnection;
> > >   7 import org.apache.hadoop.hbase.client.HConnectionManager;
> > >   8 import org.apache.hadoop.hbase.client.HTableInterface;
> > >   9 import org.apache.hadoop.hbase.client.Put;
> > >  10 import org.apache.hadoop.hbase.util.Bytes;
> > >  11
> > >  12 public class TestConnnection {
> > >  13   public static void main(String[] args) throws IOException {
> > >  14     Configuration config = HBaseConfiguration.create();
> > >  15     for (int i = 0; i < 1000; i++) {
> > >  16       HConnection connection =
> > > HConnectionManager.createConnection(config);
> > >  17       HTableInterface table =
> > > connection.getTable(TableName.valueOf("table1"));
> > >  18       byte [] cf = Bytes.toBytes("t");
> > >  19       try {
> > >  20         byte [] bytes = Bytes.toBytes(i);
> > >  21         Put p = new Put(bytes);
> > >  22         p.add(cf, cf, bytes);
> > >  23         table.put(p);
> > >  24       } finally {
> > >  25         table.close();
> > >  26         connection.close();
> > >  27       }
> > >  28       System.out.println("i=" + i);
> > >  29     }
> > >  30   }
> > >  31 }
> > >
> > >
> > > ....
> > > 2014-12-12 11:26:10,397 INFO  [main] zookeeper.RecoverableZooKeeper:
> > > Process identifier=hconnection-0x70dfa475 connecting to ZooKeeper
> > > ensemble=localhost:2181
> > > 2014-12-12 11:26:10,397 INFO  [main] zookeeper.ZooKeeper: Initiating
> > client
> > > connection, connectString=localhost:2181 sessionTimeout=90000
> > > watcher=hconnection-0x70dfa475, quorum=localhost:2181, baseZNode=/hbase
> > > 2014-12-12 11:26:10,398 INFO  [main-SendThread(localhost:2181)]
> > > zookeeper.ClientCnxn: Opening socket connection to server localhost/
> > > 127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown
> > > error)
> > > 2014-12-12 11:26:10,398 INFO  [main-SendThread(localhost:2181)]
> > > zookeeper.ClientCnxn: Socket connection established to localhost/
> > > 127.0.0.1:2181, initiating session
> > > 2014-12-12 11:26:10,401 INFO  [main-SendThread(localhost:2181)]
> > > zookeeper.ClientCnxn: Session establishment complete on server
> localhost/
> > > 127.0.0.1:2181, sessionid = 0x14a3fe0664b083a, negotiated timeout =
> > 40000
> > > 2014-12-12 11:26:10,405 DEBUG [main] client.ClientSmallScanner:
> Finished
> > > with small scan at {ENCODED => 1588230740, NAME => 'hbase:meta,,1',
> > > STARTKEY => '', ENDKEY => ''}
> > > 2014-12-12 11:26:10,406 INFO  [main]
> > > client.HConnectionManager$HConnectionImplementation: Closing zookeeper
> > > sessionid=0x14a3fe0664b083a
> > > 2014-12-12 11:26:10,407 INFO  [main] zookeeper.ZooKeeper: Session:
> > > 0x14a3fe0664b083a closed
> > > 2014-12-12 11:26:10,407 INFO  [main-EventThread] zookeeper.ClientCnxn:
> > > EventThread shut down
> > > i=997
> > > 2014-12-12 11:26:10,511 INFO  [main] zookeeper.RecoverableZooKeeper:
> > > Process identifier=hconnection-0x22a7106 connecting to ZooKeeper
> > > ensemble=localhost:2181
> > > 2014-12-12 11:26:10,511 INFO  [main] zookeeper.ZooKeeper: Initiating
> > client
> > > connection, connectString=localhost:2181 sessionTimeout=90000
> > > watcher=hconnection-0x22a7106, quorum=localhost:2181, baseZNode=/hbase
> > > 2014-12-12 11:26:10,512 INFO  [main-SendThread(localhost:2181)]
> > > zookeeper.ClientCnxn: Opening socket connection to server
> > > localhost/0:0:0:0:0:0:0:1:2181. Will not attempt to authenticate using
> > SASL
> > > (unknown error)
> > > 2014-12-12 11:26:10,512 INFO  [main-SendThread(localhost:2181)]
> > > zookeeper.ClientCnxn: Socket connection established to
> > > localhost/0:0:0:0:0:0:0:1:2181, initiating session
> > > 2014-12-12 11:26:10,515 INFO  [main-SendThread(localhost:2181)]
> > > zookeeper.ClientCnxn: Session establishment complete on server
> > > localhost/0:0:0:0:0:0:0:1:2181, sessionid = 0x14a3fe0664b083b,
> negotiated
> > > timeout = 40000
> > > 2014-12-12 11:26:10,519 DEBUG [main] client.ClientSmallScanner:
> Finished
> > > with small scan at {ENCODED => 1588230740, NAME => 'hbase:meta,,1',
> > > STARTKEY => '', ENDKEY => ''}
> > > 2014-12-12 11:26:10,521 INFO  [main]
> > > client.HConnectionManager$HConnectionImplementation: Closing zookeeper
> > > sessionid=0x14a3fe0664b083b
> > > 2014-12-12 11:26:10,521 INFO  [main] zookeeper.ZooKeeper: Session:
> > > 0x14a3fe0664b083b closed
> > > 2014-12-12 11:26:10,521 INFO  [main-EventThread] zookeeper.ClientCnxn:
> > > EventThread shut down
> > > i=998
> > > 2014-12-12 11:26:10,627 INFO  [main] zookeeper.RecoverableZooKeeper:
> > > Process identifier=hconnection-0x3822f407 connecting to ZooKeeper
> > > ensemble=localhost:2181
> > > 2014-12-12 11:26:10,627 INFO  [main] zookeeper.ZooKeeper: Initiating
> > client
> > > connection, connectString=localhost:2181 sessionTimeout=90000
> > > watcher=hconnection-0x3822f407, quorum=localhost:2181, baseZNode=/hbase
> > > 2014-12-12 11:26:10,628 INFO  [main-SendThread(localhost:2181)]
> > > zookeeper.ClientCnxn: Opening socket connection to server localhost/
> > > 127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown
> > > error)
> > > 2014-12-12 11:26:10,629 INFO  [main-SendThread(localhost:2181)]
> > > zookeeper.ClientCnxn: Socket connection established to localhost/
> > > 127.0.0.1:2181, initiating session
> > > 2014-12-12 11:26:10,631 INFO  [main-SendThread(localhost:2181)]
> > > zookeeper.ClientCnxn: Session establishment complete on server
> localhost/
> > > 127.0.0.1:2181, sessionid = 0x14a3fe0664b083c, negotiated timeout =
> > 40000
> > > 2014-12-12 11:26:10,637 DEBUG [main] client.ClientSmallScanner:
> Finished
> > > with small scan at {ENCODED => 1588230740, NAME => 'hbase:meta,,1',
> > > STARTKEY => '', ENDKEY => ''}
> > > 2014-12-12 11:26:10,638 INFO  [main]
> > > client.HConnectionManager$HConnectionImplementation: Closing zookeeper
> > > sessionid=0x14a3fe0664b083c
> > > 2014-12-12 11:26:10,639 INFO  [main] zookeeper.ZooKeeper: Session:
> > > 0x14a3fe0664b083c closed
> > > 2014-12-12 11:26:10,639 INFO  [main-EventThread] zookeeper.ClientCnxn:
> > > EventThread shut down
> > > i=999
> > >
> > >
> > >
> > >
> > > On Fri, Dec 12, 2014 at 10:22 AM, Serega Sheypak <
> > serega.sheypak@gmail.com
> > > >
> > > wrote:
> > >
> > > > Hi, I'm using CDH 5.2, 0.98
> > > > I don't know how to use it correctly. I've just used this sample:
> > > >
> > > >
> > >
> >
> https://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HConnectionManager.html
> > > >
> > > >  HConnection connection =
> HConnectionManager.createConnection(config);
> > > >  HTableInterface table =
> > > connection.getTable(TableName.valueOf("table1"));
> > > >  try {
> > > >    // Use the table as needed, for a single operation and a single
> > thread
> > > >  } finally {
> > > >    table.close();
> > > >    connection.close();
> > > >  }
> > > >
> > > >
> > > > Functional testing OK, performance fails :((((
> > > >
> > > >
> > > >
> > > > 2014-12-12 19:32 GMT+03:00 Stack <stack@duboce.net>:
> > > > >
> > > > > Does zk count go up on each request to the servlet? Which version
> of
> > > > hbase
> > > > > so can try on this end?  Do you have some client-side log? Better
> if
> > > you
> > > > > cache the connection rather than make it each time since setup is
> > > costly
> > > > > but lets fix first problem first.
> > > > > St.Ack
> > > > >
> > > > > On Fri, Dec 12, 2014 at 2:47 AM, Serega Sheypak <
> > > > serega.sheypak@gmail.com>
> > > > > wrote:
> > > > >
> > > > > > Hi, I'm using HConnectionManager from java servlet
> > > > > > Looks like it's leaking, all my zookeepers complains that there
> is
> > > too
> > > > > many
> > > > > > connections from servlet hosts.
> > > > > > Typical line from lZK log:
> > > > > >
> > > > > > oo many connections from /my.tomcat.server.com  - max is 60
> > > > > >
> > > > > >
> > > > > > Here is code sample
> > > > > >
> > > > > > public class BaseConnection {
> > > > > >
> > > > > >     private static final Logger LOG =
> > > > > > LoggerFactory.getLogger(BaseConnection.class);
> > > > > >
> > > > > >     protected void close(HConnection connection){
> > > > > >         try{
> > > > > >             if(connection == null){
> > > > > >                 return;
> > > > > >             }
> > > > > >             connection.close();
> > > > > >         }
> > > > > >         catch (Exception e){
> > > > > >             LOG.warn("Error while closing HConnection", e);
> > > > > >         }
> > > > > >     }
> > > > > >
> > > > > >     protected void close(HTableInterface hTable){
> > > > > >         try{
> > > > > >             if(hTable == null){
> > > > > >                 return;
> > > > > >             }
> > > > > >             hTable.close();
> > > > > >         }
> > > > > >         catch (Exception e){
> > > > > >             LOG.warn("Error while closing HTable", e);
> > > > > >         }
> > > > > >     }
> > > > > > }
> > > > > >
> > > > > > sample PUT code from subclass:
> > > > > >
> > > > > > public void put(List<MyBean> entries){
> > > > > >     HConnection hConnection = null;
> > > > > >     HTableInterface hTable = null;
> > > > > >     try {
> > > > > >         List<Put> puts = new ArrayList<Put>(entries.size());
> > > > > >         for(MyBean myBean : entries){
> > > > > >             puts.add(new MyBeanSerDe().createPut(myBean));
> > > > > >         }
> > > > > >         hConnection =
> > > > HConnectionManager.createConnection(configuration);
> > > > > >         hTable = hConnection.getTable(NAME_B);
> > > > > >         hTable.put(puts);
> > > > > >
> > > > > >     }catch (Exception e){
> > > > > >         LOG.error("Error while doing bulk put", e);
> > > > > >     }finally{
> > > > > >         close(hTable);
> > > > > >         close(hConnection);
> > > > > >     }
> > > > > > }
> > > > > >
> > > > >
> > > >
> > >
> >
>

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