• archivelog huge generation


    select
    trunc(completion_time) as "Date"
    ,count(*) as "Count"
    ,((sum(blocks * block_size)) /1024 /1024) as "MB"
    from v$archived_log
    group by trunc(completion_time);

    SELECT TRUNC (COMPLETION_TIME, 'HH') ARCHIVED_DATE_HOUR,
    ROUND (SUM (BLOCKS * BLOCK_SIZE) / 1024 / 1024, 0) SIZE_IN_MB
    FROM V$ARCHIVED_LOG
    GROUP BY TRUNC (COMPLETION_TIME, 'HH')
    ORDER BY 1;


    col program for a10
    col username for a10
    select to_char(sysdate,'hh24:mi'), username, program , a.sid, a.serial#, b.name, c.value
    from v$session a, v$statname b, v$sesstat c
    where b.STATISTIC# =c.STATISTIC#
    and c.sid=a.sid and b.name like 'redo%'
    order by value;


    select * from dba_tab_modifications
    where table_owner <> 'SYS'
    order by updates desc;

    I have googled for you and found a couple of good queries and metalink docs to drill down this issue.

    select s.username, s.osuser, s.status,s.sql_id, sr.* from
    (select sid, round(value/1024/1024) as "RedoSize(MB)"
    from v$statname sn, v$sesstat ss
    where sn.name = 'redo size'
    and ss.statistic# = sn.statistic#
    order by value desc) sr,
    v$session s
    where sr.sid = s.sid
    and rownum <= 10;

    ------------------------------------

    select s.sid, n.name, s.value, sn.username, sn.program, sn.type, sn.module
    from v$sesstat s
    join v$statname n on n.statistic# = s.statistic#
    join v$session sn on sn.sid = s.sid
    where name like '%redo entries%'
    order by value desc;

    SQL: How to Find Sessions Generating Lots of Redo or Archive logs (Doc ID 167492.1)

    Master Note: Troubleshooting Redo Logs and Archiving(Doc ID 1507157.1]

    Troubleshooting High Redo Generation Issues(Doc ID 782935.1)


    Archivelog generation on a daily basis:

    set pages 1000
    select trunc(COMPLETION_TIME,'DD') Day, thread#, round(sum(BLOCKS*BLOCK_SIZE)/1048576) MB,count(*) Archives_Generated from v$archived_log
    group by trunc(COMPLETION_TIME,'DD'),thread# order by 1;
    Archive log generation on an hourly basis:

    set pages 1000
    select trunc(COMPLETION_TIME,'HH') Hour,thread# , round(sum(BLOCKS*BLOCK_SIZE)/1048576) MB,count(*) Archives from v$archived_log
    group by trunc(COMPLETION_TIME,'HH'),thread# order by 1 ;

    the following script is useful to find the archivelog switches on an hourly basis that happened in the past one week:

    SELECT to_date(first_time) DAY,
    to_char(sum(decode(to_char(first_time,'HH24'),'00',1,0)),'99') "00",
    to_char(sum(decode(to_char(first_time,'HH24'),'01',1,0)),'99') "01",
    to_char(sum(decode(to_char(first_time,'HH24'),'02',1,0)),'99') "02",
    to_char(sum(decode(to_char(first_time,'HH24'),'03',1,0)),'99') "03",
    to_char(sum(decode(to_char(first_time,'HH24'),'04',1,0)),'99') "04",
    to_char(sum(decode(to_char(first_time,'HH24'),'05',1,0)),'99') "05",
    to_char(sum(decode(to_char(first_time,'HH24'),'06',1,0)),'99') "06",
    to_char(sum(decode(to_char(first_time,'HH24'),'07',1,0)),'99') "07",
    to_char(sum(decode(to_char(first_time,'HH24'),'08',1,0)),'99') "08",
    to_char(sum(decode(to_char(first_time,'HH24'),'09',1,0)),'99') "09",
    to_char(sum(decode(to_char(first_time,'HH24'),'10',1,0)),'99') "10",
    to_char(sum(decode(to_char(first_time,'HH24'),'11',1,0)),'99') "11",
    to_char(sum(decode(to_char(first_time,'HH24'),'12',1,0)),'99') "12",
    to_char(sum(decode(to_char(first_time,'HH24'),'13',1,0)),'99') "13",
    to_char(sum(decode(to_char(first_time,'HH24'),'14',1,0)),'99') "14",
    to_char(sum(decode(to_char(first_time,'HH24'),'15',1,0)),'99') "15",
    to_char(sum(decode(to_char(first_time,'HH24'),'16',1,0)),'99') "16",
    to_char(sum(decode(to_char(first_time,'HH24'),'17',1,0)),'99') "17",
    to_char(sum(decode(to_char(first_time,'HH24'),'18',1,0)),'99') "18",
    to_char(sum(decode(to_char(first_time,'HH24'),'19',1,0)),'99') "19",
    to_char(sum(decode(to_char(first_time,'HH24'),'20',1,0)),'99') "20",
    to_char(sum(decode(to_char(first_time,'HH24'),'21',1,0)),'99') "21",
    to_char(sum(decode(to_char(first_time,'HH24'),'22',1,0)),'99') "22",
    to_char(sum(decode(to_char(first_time,'HH24'),'23',1,0)),'99') "23"
    from
    v$log_history
    where to_date(first_time) > sysdate -8
    GROUP by
    to_char(first_time,'YYYY-MON-DD'), to_date(first_time)
    order by to_date(first_time)
    /

    ##################################################################################

    > Check which session is generating more redo.

    rem -----------------------------------------------------------------------

    rem Purpose: Transaction which generating more redo

    rem This view contains the column BLOCK_CHANGES which indicates how much blocks have been changed

    rem by the session. High values indicate a session generating lots of redo.

    rem Run the query multiple times and examine the delta between each occurrence

    rem of BLOCK_CHANGES. Large deltas indicate high redo generation by the session.

    rem -----------------------------------------------------------------------

    set pages 1000

    set lines 140

    SELECT s.sid, s.serial#, s.username, s.program,
    i.block_changes
    FROM v$session s, v$sess_io i
    WHERE s.sid = i.sid
    ORDER BY 5 desc, 1, 2, 3, 4;

    #############################Size of teh archives per each day wise ############

    select decode(grouping (trunc(COMPLETION_TIME)),1,'TOTAL',TRUNC(COMPLETION_TIME)) TIME, SUM(BLOCKS * BLOCK_SIZE)/1024/1024/1024 SIZE_MB from V$ARCHIVED_LOG group by cube (trunc (COMPLETION_TIME)) order by 1

    /

    As per my understanding if the log switches per hour 60 is not better practice and i would recommend to increase the size of the redo log as you said from 1G to 5G.

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  • 原文地址:https://www.cnblogs.com/yaoyangding/p/14609126.html
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