title: PostgreSQL insert data always fail process hang up
body: <p>When i want insert a row to table.
  It always hangs on waiting can not commit successful.</p>
  
  <pre><code>postgres 17941  2092  0 16:42 ?        00:00:00 /usr/lib/postgresql/9.1/bin/postgres -D /var/lib/postgresql/9.1/main -c config_file=/etc/postgresql/9.1/main/postgresql.conf
  postgres 17943 17941  0 16:42 ?        00:00:00 postgres: writer process                                                                                                    
  postgres 17944 17941  0 16:42 ?        00:00:00 postgres: wal writer process                                                                                                
  postgres 17945 17941  0 16:42 ?        00:00:00 postgres: autovacuum launcher process                                                                                       
  postgres 17946 17941  0 16:42 ?        00:00:00 postgres: stats collector process                                                                                           
  postgres 18326 17941  0 16:51 ?        00:00:00 postgres: admin gt_development 127.0.0.1(40309) COMMIT waiting for 0/1217CA98   
  </code></pre>
  
  <p>Who can help me?</p>