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From stack <st...@duboce.net>
Subject Re: Does HBASE allow multiple clients write to the same table?
Date Tue, 07 Jul 2009 04:14:33 GMT
Does the warning indicate a break in connection to hbase?  After it happens,
no more updates make it through?

Your code looks fine.

St.Ack


On Sun, Jul 5, 2009 at 8:38 PM, <y_823910@tsmc.com> wrote:

> Hi Nitay,
>
> By counting the table records, I found it's ok to put data by multiple
> clients until the warning occured.
>
> In order to improve my put speed, I create a thread with HTable.
> Something wrong with my codes?
>
>
> class Thread2HBase extends Thread {
>
>              public void saveData2HBase(ResultSet rs,String
> TableName,String KeyColumn,String FamColumn,Vector<String> ColumnList){
>            HTable  table = new HTable(this.config, TableName);
>             // table.setAutoFlush(false);
>             table.setWriteBufferSize(1024*1024*12);
>            //===================================================
>            Put p ;
>            String tmp="";
>            while (rs.next()) {
>                  p = new Put(Bytes.toBytes(rs.getString(KeyColumn)));
>                  Enumeration<String> columns =ColumnList.elements();
>                  while(columns.hasMoreElements()){
>                      String column = (String)columns.nextElement();
>                      if (rs.getString(column)==null){
>                        tmp="";
>                     }else{
>                        tmp=rs.getString(column);
>                     }
>                     p.add(Bytes.toBytes(FamColumn),
> Bytes.toBytes(column),Bytes.toBytes(tmp));
>                   }
>                   table.put(p);
>             }
>             table.close();
>      }
>
> }
>
>
>
>                      Nitay
>                      <nitayj@gmail.com        To:
> hbase-user@hadoop.apache.org
>                      >                        cc:      (bcc: Y_823910/TSMC)
>                                               Subject: Re: Does HBASE allow
> multiple clients write to the same table?
>                      2009/07/03 02:10
>                      PM
>                      Please respond to
>                      hbase-user
>
>
>
>
>
>
> Hi Fleming,
>
> That warning is harmless. It should recover after such things. If you ever
> see some fatal problems (crashes, data loss, corruption, etc) after such a
> thing let us know.
>
> HBase should handle multiple clients writing to the same table fine. You
> will get better performance if they are writing to different regions (i.e.
> random data), as then the load is split between multiple region serving
> nodes.
>
> -n
>
> On Thu, Jul 2, 2009 at 9:28 PM, <y_823910@tsmc.com> wrote:
>
> > Hi there,
> >
> > Now I use HTable to put my oracle table data to HBASE.
> > In order to enhance the speed, I create a few HTable clients to put the
> > data.
> > It occured only some WARN like "WARN zookeeper.ClientCnxn: Exception
> > closing session",
> > not fetal error,evently I found there's no data increase in HBASE.
> > Any HBASE setting about the client connection limitation?
> > Or HBASE doesn't allow multiple clients write to the same table.
> > Any suggestion?
> > Thank you
> >
> > Fleming
> >
> >
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