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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 19:38:59 GMT
Great, I'll refactor the code. and report back

2014-12-13 22:36 GMT+03:00 Stack <stack@duboce.net>:
>
> On Sat, Dec 13, 2014 at 11:33 AM, Serega Sheypak <serega.sheypak@gmail.com
> >
> wrote:
> >
> > So the idea is
> > 1. instantiate HConnection using HConnectionManager once
> > 2. Create HTable instance for each Servlet.doPost and close after
> operation
> > is done.
> > Is that correct?
> >
>
>
> Yes.
>
>
>
> >
> > Do region locations cached in this case?
> > Are ZK connections to region/ZK reused?
> >
>
> Yes
>
>
> > Can I "harm" put/get data because of Servlet concurrency? Each connection
> > could be used in many threads fro different HTable instances for the same
> > HBase table?
> >
> >
> Its a bug if the above has issues.
>
> St.Ack
>
>
>
> >
> > 2014-12-13 22:21 GMT+03:00 lars hofhansl <larsh@apache.org>:
> > >
> > > Note also that the createConnection part is somewhat expensive
> (creates a
> > > new thread pool for use with Puts, also does a ZK lookup, etc).If
> > possible
> > > create the connection ahead of time and only get/close an HTable per
> > > request/thread.
> > > -- Lars
> > >       From: Serega Sheypak <serega.sheypak@gmail.com>
> > >  To: user <user@hbase.apache.org>
> > >  Sent: Friday, December 12, 2014 11:45 AM
> > >  Subject: Re: HConnectionManager leaks with zookeeper conection oo many
> > > connections from /my.tomcat.server.com - max is 60
> > >
> > > i have 10K doPost/doGet requests per second.
> > > 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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