Difference between revisions of "Performance"

Revision as of 09:27, 16 February 2014

• Memory Management through the versions
• Automatic Memory Management discussion with Tom Kyte
• Automatic Memory Management from ORACLE_BASE
• Tuning

How many log switches have ocurred per hour over the past week?

set lines 200
select * from (
select TO_DATE(first_time,'DD-MON-RR') day,
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'00',1,0)),'999') "00",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'01',1,0)),'999') "01",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'02',1,0)),'999') "02",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'03',1,0)),'999') "03",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'04',1,0)),'999') "04",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'05',1,0)),'999') "05",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'06',1,0)),'999') "06",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'07',1,0)),'999') "07",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'08',1,0)),'999') "08",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'09',1,0)),'999') "09",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'10',1,0)),'999') "10",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'11',1,0)),'999') "11",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'12',1,0)),'999') "12",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'13',1,0)),'999') "13",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'14',1,0)),'999') "14",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'15',1,0)),'999') "15",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'16',1,0)),'999') "16",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'17',1,0)),'999') "17",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'18',1,0)),'999') "18",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'19',1,0)),'999') "19",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'20',1,0)),'999') "20",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'21',1,0)),'999') "21",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'22',1,0)),'999') "22",
       TO_CHAR(sum(decode(to_char(first_time,'HH24'),'23',1,0)),'999') "23"
from   v$log_history
group  by to_date (first_time,'DD-MON-RR')
order  by 1 desc
)
where  rownum < 8;