oracle日志生成量

• Gather daily history of primary database's redo generation rate using this query.

  COPY

  SQL> select trunc(completion_time) as "DATE", count(*) as "LOG SWITCHES", round(sum(blocks*block_size)/1024/1024) as "REDO PER DAY (MB)" from v$archived_log where dest_id=1 group by trunc(completion_time) order by 1;

• Gather the peak redo rate for each hour.

  COPY

  select begin_time,instance_number,metric_name, round(value/1024/1024) "Max Rate in MB" from (select to_char(begin_time,'DD-MON-YYYY HH24') begin_time,instance_number,metric_name,max(value) value from dba_hist_sysmetric_history where metric_name = 'Redo Generated Per Sec' and trunc(begin_time) >=trunc(sysdate-7) group by to_char(begin_time,'DD-MON-YYYY HH24'),instance_number,metric_name) order by 1,3;

  Optionally change the '7' to some other value to change the number of days in the output.

  The preferred query is dba_hist_sysmetric_history because it provides more precise information, but the retention is limited by AWR retention. If the dates you are looking for are not available form the previous query, gather per log redo generation rate using v$archived_log instead.

  COPY

  SQL> alter session set nls_date_format='YYYY/MM/DD HH24:MI:SS'; SQL> select thread#,sequence#,blocks*block_size/1024/1024 MB,(next_time-first_time)*86400 sec, blocks*block_size/1024/1024)/((next_time-first_time)*86400) "MB/s" from v$archived_log where ((next_time-first_time)*86400<>0) and first_time between to_date('2024/10/15 08:00:00','YYYY/MM/DD HH24:MI:SS') and to_date('2024/11/15 11:00:00','YYYY/MM/DD HH24:MI:SS') and dest_id=1 order by first_time;

• Gather hourly snapshots of the redo generation rate from the Automatic Workload Repository (AWR) report 6 hours before the start of any redo or transport lag.

  By default, Oracle Database automatically generates snapshots once every hour; however, you may want to manually create snapshots to capture statistics at times different from those of the automatically generated snapshots. To view information about an existing snapshot, use the DBA_HIST_SNAPSHOT view.

https://docs.oracle.com/en/database/oracle/oracle-database/26/haovw/tune-and-troubleshoot-oracle-data-guard1.html#GUID-52FD3117-AED0-4947-A429-8865FF89E697