LoadBalance strategies

The LoadBalance mode of OceanBase Connector/J is used to create a connection for each connection object. Each time a connection object is created, a host is selected from the host list by using the SLB policy to create a connection. Profile-based LoadBalance can monitor the corresponding configuration file directory and realize it after updating the configuration file. You can update the SLB policy, host list, and other information without modifying the URL each time you execute getConnection.

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 URL Option. The following table describes the valid values of the parameters.

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 valid value of the parameter.

Blacklist strategies

OceanBase Connector/J allows you to specify blacklist strategies by setting the following two sub-parameters of the OBLB_BLACKLIST parameter. The blacklist entry removal strategy can be configured by setting the REMOVE_STRATEGY sub-parameter. The blacklist entry adding strategies can be configured by setting theAPPEND_STRATEGY sub-parameter.

OceanBase Connector/J supports two blacklist entry adding strategies, which correspond to the APPEND_STRATEGY sub-parameter. The following table describes the valid values of the sub-parameter.

OceanBase Connector/J supports only one blacklist removal strategy, which corresponds to the REMOVE_STRATEGY sub-parameter. The following table describes the valid value of the sub-parameter.

Examples of blacklist 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);

Parameters