oracle 11.2.0.1 rac

dba_2pc_pending增长异常,每天增加2-3w.
导致很多系统操作非常消耗io.

监控里可以看到类似的语句：

Elapsed Elapsed Time Time (s) Executions per Exec (s) %Total %CPU %IO SQL Id---------------- -------------- ------------- ------ ------ ------ ------------ 39,249.8 844 46.50 5.2 31.5 42.3 1whtta179zmk9select count(*) from pending_sub_sessions$ where local_tran_id = :1 19,724.7 883 22.34 2.6 32.5 42.2 5ryqf4hgc790zselect count(*) from pending_sessions$ where local_tran_id = :1 Elapsed Elapsed Time Time (s) Executions per Exec (s) %Total %CPU %IO SQL Id---------------- -------------- ------------- ------ ------ ------ ------------- 118,896.1 883 134.65 28.5 35.9 41.6 6yva4jbyzfky5select local_tran_id, state, status, heuristic_dflt, session_vector, reco_vector, global_commit#, type# from pending_trans$ pt where global_tran_fmt = :1 and (global_oracle_id = :2 or global_foreign_id = :3) and session_vector != '00000000' and exists (select * from pending_sessions$
暂时没有找到根本解决方法，一个临时性的方案如下：

清除以下三个基表
truncate pending_sub_sessions$;
truncate pending_trans$;truncate pending_sessions$;