时间：
select sql_id,sid,serial#,username,target ,sql_plan_operation,sofar blocks_read,totalwork total_blocks,round(time_remaining/60) minutes from v$session_longops where sofar<>totalwork and username='XXX'
sofar : Units of work done so far for the operation specified in the OPNAME column 这个值会一直增加,就是截止到目前所统计出的工作总量，而这里用了where sofar<>totalwork的含义代表就是此事务还没结束，因为结束了sofar会等于totalwork.
Totalwork:Total units of work for the operation specified in the OPNAME column 预估出的总数据块读取量，不会改变
Time_remaining:Estimate (in seconds) of time remaining for the operation to complete
V$SESSION_LONGOPS displays the status of various operations that run for longer than 6 seconds (in absolute time). These operations currently include many backup and recovery functions, statistics gathering, and query execution, and more operations are added for every Oracle release.
官方文档并未对v$session_longops原理做详细的介绍，想要通过v$session_longops监控一个操作，需要满足以下条件：
1 执行操作超过6秒 2 执行操作访问数据块必须大于10000 3 必须设置了TIMED_STATISTICS或者打开了SQL_TRACE 4 执行操作中的对应必须通过DBMS_STATS或ANALYZE进行了分析
在以上基础上再关联v$sql.
IO
select sql_id,disk_reads from (select sql_id,buffer_gets,disk_reads,sorts,cpu_time/1000000 cpu,rows_processed,elapsed_time from v$sqlstats order by disk_reads desc
--- 具体要依据什么信息排序可适当选择,而此视图里的多项值是累积的
