通常情况下,dg库的硬件资源都是不如主库硬件资源的,一般为主库的1/2,
那么如果主库产生归档过快那么dg库有可能日志应用不过来,可以尝试通过调整一下参数加快归档日志应用;
前方高等!!!
在standby端执行,千万不可在primary端调整!!
1>
alter system set parallel_execution_message_size=32768 scope=spfile; --默认16384
alter system set filesystemio_options=setall scope=spfile; --默认 none
alter system set disk_asynch_io=true scope=spfile; --默认就是true
alter system set db_lost_write_protect=typical scope=spfile ; --默认是full
alter system set db_block_checksum=false scope=spfile ; --默认是TYPICAL
alter system set DB_BLOCK_CHECKING=false scope=spfile ; --默认是false
alter system set db_writer_processes=8 scope=spfile; --默认是6个
shutdown immediate;
startup nomount;
alter database mount standby database;
alter database recover managed standby database parallel 4 disconnect from session; ----并行度根据CPU核数*2设定
另外shared_pool size过小也会影响应用速度,请遇到DG延迟的时候 可适当根据安装规范检查,防止shared pool过小。(如最小要保证2G以上)
2> dg库日志应用性能监控
set lines 200 pages 2000
col process format a8
col spid format a8
col event format a50 tru
col SIW format 999999
select to_char(sysdate,'DD-MON-YYYY HH24:MI:SS') "Current time"
,s.process
, p.spid
, substr(s.program, -6) PROC
, s.event
, s.p1
, s.p2
, s.p3
, s.seconds_in_wait SIW
, s.seq#
from v$session s, v$process p
where p.addr = s.paddr and (s.program like '%MRP%' or s.program like '%PR0%' or s.program like '%DBW%' or s.program like '%CKPT%')
order by s.process
/