Yes thats correct. HTable is not thread-safe. On Mon, Nov 24, 2014 at 2:55 PM, Liu, Ming (HPIT-GADSC) <ming.l...@hp.com> wrote:
> Thank you Bharath, > > This is a very helpful reply! I will share the connection between two > threads. Simply put, HTable is not safe for multi-thread, is this true? In > multi-threads, one must use HConnectionManager. > > Thanks, > Ming > -----Original Message----- > From: Bharath Vissapragada [mailto:bhara...@cloudera.com] > Sent: Monday, November 24, 2014 4:52 PM > To: hbase-user > Subject: Re: What is proper way to make a hbase connection? using HTable > (conf,tbl) or createConnection? Zookeeper session run out. > > Hi Ming, > > HConnection connection = HConnectionManager.createConnection(conf); > HTableInterface table = connection.getTable("mytable"); table.get(...); / > table.put(...); > > Is the correct way to use. However > HConnectionManager.createConnection(conf) gives you a "shared" > HConnection which you can reuse across multiple threads that get their own > conn.getTable() and do their puts/gets. > > Thanks, > Bharath > > On Mon, Nov 24, 2014 at 2:03 PM, Liu, Ming (HPIT-GADSC) <ming.l...@hp.com> > wrote: > > > Hello, > > > > I am using HBase 0.98.5. In example hbase client programs, some use > > createConnection() and some use HTable() directly, I found they behave > > different, I wrote two simple tests program using these two different > > methods, each program will start two threads and do simple put. and I > > found: > > One program will start only 1 zookeeper sessions shared in two threads > > while another will start 2 zookeeper sessions. So I don't know why the > > program using createConnection will do more zookeeper requests than > > simply use HTable. Is it possible to use createConnection in two > > threads but share the same zookeeper session? > > > > Here is details: > > Demo1 will make two zookeeper sessions, seems two HBase connections; > > but > > Demo2 will only make one zookeeper session. My real program is using > > createConnection in multiple threads as in demo1, since I have a very > > small zookeeper , it only allows 60 concurrent sessions, so my program > > always fail when there are hundreds of threads started. But I saw if > > using HTable directly, it will only consume 1 zookeeper session. But > > it will change a lot in my current program, so I wish there is a way > > to use createConnection and behave same as using HTable, is it possible? > > > > Source code: > > > > Demo1.java > > class ClientThread extends Thread > > { > > public static Configuration configuration; > > static { > > configuration = HBaseConfiguration.create(); > > } > > public void run() > > { > > try { > > System.out.println("start insert data ......"); > > HConnection > > con=HConnectionManager.createConnection(configuration); > > HTable table = (HTable)con.getTable("hbase_table1"); > > Put put = new Put("1".getBytes()); > > put.add("c1".getBytes(), null, "baidu".getBytes()); > > put.add("c2".getBytes(), null, "http://www.baidu.com1 > > ".getBytes()); > > try { > > table.put(put); > > } catch (IOException e) { > > e.printStackTrace(); > > } > > System.out.println("end insert data ......"); > > } > > catch (Exception e) { > > } > > > > } > > } > > public class demo1 { > > > > public static void main(String[] args) throws Exception { > > Thread t1=new ClientThread(); > > Thread t2=new ClientThread(); > > t1.start(); > > t2.start(); > > } > > > > } > > > > > > Demo2.java > > class ClientThread1 extends Thread > > { > > public static Configuration configuration; > > static { > > configuration = HBaseConfiguration.create(); > > } > > public void run() > > { > > System.out.println("start insert data ......"); > > try { > > HTableInterface table = new > > HTable(configuration, "hbase_table1"); > > Put put = new Put("1".getBytes()); > > put.add("c1".getBytes(), null, > "baidu".getBytes()); > > put.add("c2".getBytes(), null, " > > http://www.baidu.com1".getBytes()); > > table.put(put); > > } catch (Exception e) { > > e.printStackTrace(); > > } > > System.out.println("end insert data ......"); > > > > } > > > > > > } > > public class demo2 { > > > > public static void main(String[] args) throws Exception { > > Thread t1=new ClientThread1(); > > Thread t2=new ClientThread1(); > > t1.start(); > > t2.start(); > > } > > } > > > > > > > > This should be a very basic question, sorry, I really did some search > > but cannot find any good explaination. Any help will be very appreciated. > > > > Thanks, > > Ming > > > > > > -- > Bharath Vissapragada > <http://www.cloudera.com> > -- Bharath Vissapragada <http://www.cloudera.com>
