几个有用的oracle dba_hist_*查询语句
耗CPU最多的10条语句


select * from
   (select
    s.SQL_ID,
    sum(s.CPU_TIME_DELTA),
    sum(s.DISK_READS_DELTA),
    count(*)
    from DBA_HIST_SQLSTAT s
   group by s.SQL_ID
   order by sum(s.CPU_TIME_DELTA) desc
   )
where rownum < 11
/

最近7天，指定时间段（8:00-16:00）最消耗CPU的10条语句


select * from
   (select
      s.SQL_ID,
      sum(s.CPU_TIME_DELTA),
      sum(s.DISK_READS_DELTA),
      count(*)
    from DBA_HIST_SQLSTAT s, DBA_HIST_SNAPSHOT p
    where 1=1
     and s.SNAP_ID = p.SNAP_ID
     and EXTRACT(HOUR FROM p.END_INTERVAL_TIME) between 8 and 16
     and p.END_INTERVAL_TIME between SYSDATE-7 and SYSDATE
    group by s.SQL_ID
    order by sum(s.CPU_TIME_DELTA) desc
   )
where rownum < 11
/

可以进一步关联DBA_HIST_SQLTEXT视图得到详细的SQL语句


select * from
   (select
    s.SQL_ID, s.SQL_TEXT
    sum(s.CPU_TIME_DELTA),
    sum(s.DISK_READS_DELTA),
    count(*)
   from DBA_HIST_SQLSTAT s, DBA_HIST_SNAPSHOT p, DBA_HIST_SQLTEXT t
   where 1=1
    and s.SNAP_ID = p.SNAP_ID
    and s.SQL_ID = t.SQL_ID
    and EXTRACT(HOUR FROM p.END_INTERVAL_TIME) between 8 and 16
    and t.COMMAND_TYPE != 47 –- Exclude PL/SQL blocks from output
    and p.END_INTERVAL_TIME between SYSDATE-7 and SYSDATE
   group by s.SQL_ID
   order by sum(s.CPU_TIME_DELTA) desc
   )
where rownum < 11
/

分析指定SQL语句各版本执行计划的资源消耗情况


select st.SQL_ID,
   st.PLAN_HASH_VALUE,
   sum(st.EXECUTIONS_DELTA) EXECUTIONS,
   sum(st.ROWS_PROCESSED_DELTA) CROWS,
   trunc(sum(st.CPU_TIME_DELTA)/1000000/60) CPU_MINS,
   trunc(sum(st.ELAPSED_TIME_DELTA)/1000000/60)  ELA_MINS
from DBA_HIST_SQLSTAT st
where st.SQL_ID in (‘&1′)
group by st.SQL_ID , st.PLAN_HASH_VALUE
order by st.SQL_ID, CPU_MINS;

分析对比SQL语句在不同执行计划中的执行情况


SELECT st2.SQL_ID,
   st2.PLAN_HASH_VALUE,
   st_long.PLAN_HASH_VALUE l_PLAN_HASH_VALUE,
   st2.CPU_MINS,
   st_long.CPU_MINS l_CPU_MINS,
   st2.ELA_MINS,
   st_long.ELA_MINS l_ELA_MINS,
   st2.EXECUTIONS,
   st_long.EXECUTIONS l_EXECUTIONS,
   st2.CROWS,
   st_long.CROWS l_CROWS,
   st2.CPU_MINS_PER_ROW,
   st_long.CPU_MINS_PER_ROW l_CPU_MINS_PER_ROW
FROM
   (SELECT st.SQL_ID,
     st.PLAN_HASH_VALUE,
     SUM(st.EXECUTIONS_DELTA) EXECUTIONS,
     SUM(st.ROWS_PROCESSED_DELTA) CROWS,
     TRUNC(SUM(st.CPU_TIME_DELTA)                                         /1000000/60) CPU_MINS ,
     DECODE( SUM(st.ROWS_PROCESSED_DELTA), 0 , 0 , (SUM(st.CPU_TIME_DELTA)/1000000/60)/SUM(st.ROWS_PROCESSED_DELTA) ) CPU_MINS_PER_ROW ,
     T