判断回滚段竞争的SQL语句:(当Ratio大于2时存在回滚段竞争,需要增加更多的回滚段)select rn.name, rs.GETS, rs.WAITS, (rs.WAITS / rs.GETS) * 100 ratiofrom v$rollstat rs, v$rollname rnwhere rs.USN = rn.usn 判断恢复日志竞争的SQL语句:(immediate_contention或wait_contention的值大于1时存在竞争)select name,(t.IMMEDI…