LoadBalance strategies

The LoadBalance mode of OceanBase Connector/J is used for the creation of each Connection object. Each time a Connection object is created, OceanBase Connector/J selects a host from the host list by using the load balancing strategy to establish the connection. LoadBalance based on a configuration file can monitor the corresponding configuration file directory and detect changes after the configuration file is updated. The load balancing strategy, host list, and other information can be updated without modifying the URL each time getConnection is executed.

Load balancing strategies

You can implement three load balancing strategies of OceanBase Connector/J by configuring the OBLB_STRATEGY and LOAD_BALANCE_STRATEGY parameters in the extended configuration information and the loadBalanceStrategy parameter in the URL. The following table describes the strategies.

Load balancing group selection strategy

OceanBase Connector/J supports only one strategy for load balancing between multiple groups of hosts, which corresponds to the OBLB_GROUP_STRATEGY parameter in the extended configuration information. The following table describes the strategy.

Blocklist strategies

OceanBase Connector/J allows you to specify strategies for removing and adding blocklist entries with two sub-parameters of OBLB_BLACKLIST. Use the REMOVE_STRATEGY sub-parameter to configure removal strategies, and the APPEND_STRATEGY sub-parameter to configure addition strategies.

OceanBase Connector/J supports two blocklist entry addition strategies, which correspond to the APPEND_STRATEGY sub-parameter. The following table describes the strategies.

OceanBase Connector/J supports only one blocklist entry removal strategy, which corresponds to the REMOVE_STRATEGY sub-parameter. The following table describes the strategies.

Examples of blocklist strategies

String url = "jdbc:oceanbase:loadbalance://@(NET_SERVICE_NAME=(DESCRIPTION=
  (OBLB=ON)                                                    
  (OBLB_RETRY_ALL_DOWNS=120)
  (OBLB_GROUP_STRATEGY=ROTATION)                               
  (OBLB_BLACKLIST=
      (
        REMOVE_STRATEGY=(
          (NAME=TIMEOUT)
          (TIMEOUT=100)
        )
      )                          
      (
        APPEND_STRATEGY =(
          (NAME=RETRYDURATION)
          (RETRYTIMES=3)
          (DURATION=100)
        )
      )
  )
  (ADDRESS_LIST=
     (OBLB_STRATEGY=SERVERAFFINITY)                          
     (ADDRESS=(PROTOCOL=tcp)(HOST=host1)(PORT=port1)(WEIGHT=1))      
     (ADDRESS=(PROTOCOL=tcp)(HOST=host2)(PORT=port2)(WEIGHT=10))
  )    
  (ADDRESS_LIST=
     (OBLB_STRATEGY=RANDOM)
     (ADDRESS=(PROTOCOL=tcp)(HOST=host3)(port=port3))
     (ADDRESS=(PROTOCOL=tcp)(HOST=host4)(port=port4))
  )
  (ADDRESS_LIST=
     (OBLB_STRATEGY=ROTATION)
     (ADDRESS=(PROTOCOL=tcp)(HOST=host3)(port=port3))
     (ADDRESS=(PROTOCOL=tcp)(HOST=host4)(port=port4))
   )
   (CONNECT_DATA=(SERVICE_NAME=OBDATABASE))
))/OBDATABASE?rewriteBatchedStatements=true&allowSendParamTypes=true&prepStmtCacheSize=1000";
Connection = DriverManager.getConnection(url);

Related parameters