10g taf 分享

介绍：

没有配置 TAF的情况下，客户端连接数据库，一个节点宕机，客户端需要重新连接，才能正常连接。

通过 TAF去连接数据库时，当一个节点宕机时，无需重连，会自动切换到另外一个节点，但是前提条件是没有未提交的事务，若有未提交的事务，则会报错 ORA-25405: transaction status unknown，重新连接即可。

三种方法： Client-Side Connect time Failover、 Client-Side TAF、 Service-Side TAF

Service-Side TAF 配置

创建taf服务

srvctl add service -d test -s taf -r "test1,test2" -P BASIC

-s 服务名

-r 需要创建服务的节点的instance_name

-P taf的状态，BASIC为基础状态

-d unique name

开启taf服务

srvctl start service -d test -s taf

服务ora.TEST.taf.TEST1.srv

查看状态

srvctl status service -d TEST -s taf

查看taf服务的service_id

SQL> select name,service_id from dba_services where name='taf';

NAME                  SERVICE_ID

-------------------------------------- ----------

taf                           7

查看taf服务的信息

SQL> select name, failover_method, failover_type, failover_retries,goal, clb_goal,aq_ha_notifications  from dba_services where service_id = 7;

NAME            METHOD      TYPE        RETRIES GOAL       CLB_GOAL AQNOT

--------------- ----------- ---------- -------- ---------- -------- -----

taf                                                        LONG     NO

修改参数taf服务的参数

begin

dbms_service.modify_service(service_name        => 'taf',

                  goal                => DBMS_SERVICE.goal_throughput,

                  aq_ha_notifications => TRUE,

                  failover_method     => DBMS_SERVICE.failover_method_basic,

                  failover_type       => DBMS_SERVICE.failover_type_select,

                  failover_retries    => 10,

                  failover_delay      => 1,

                  clb_goal            => DBMS_SERVICE.clb_goal_long);

end;

/

检查配置情况

再次查看taf服务参数

SQL> select name, failover_method, failover_type, failover_retries,goal, clb_goal,aq_ha_notifications  from dba_services where service_id = 7;

NAME            METHOD      TYPE        RETRIES GOAL       CLB_GOAL AQNOT

--------------- ----------- ---------- -------- ---------- -------- -----

taf             BASIC       SELECT           10 THROUGHPUT LONG     YES

method:basic/none

type:select/session/none

failover_retries为failover重试次数

goal: throughput （数据吞吐量）/ service_time （服务时间） / none

clb_goal: long （会将服务均分给每个 rac instance ）

修改tnsname

vi  tnsnames.ora 
TAF =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = rac1-vip.yang.com)(PORT = 1521))
    (ADDRESS = (PROTOCOL = TCP)(HOST = rac2-vip.yang.com)(PORT = 1521))
    (LOAD_BALANCE = yes)
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = taf)
    )
)