dg库日志应用慢参数调整

dg库日志应用慢参数调整 1> 日志应用是否使用了并行;-并行度看主机的cpu个数 alter database recover managed standby database parallel 8 disconnect from session; 2> 调整并行恢复参数 parallel_execution_message_size 最大值65536；增加size需要更加多的share pool。 调整参数时，需要确定shared pool的使用情况，避免4031错误 show parameter parallel_execution_message_size show parameter disk_asynch_io show parameter parallel_execution_message_size alter system set parallel_execution_message_size=32768 scope=spfile; alter system set disk_asynch_io=true scope=spfile; 3> 是否使用异步io；通常异步io能提供更好的io性能；aix hp 貌似默认是开启异步io的 alter system set filesystemio_options=setall; show parameter filesystemio_options 4> db_block_checking --块内数据逻辑检查 在dg库上取消该参数，能提供更好的性能，经过测试能提升约2倍速度   alter system set db_block_checking=false scope=spfile; startup nomount; alter database mount standby database; -------------------------------------------- alter system set parallel_execution_message_size=32768 scope=spfile;  alter system set filesystemio_options=setall scope=spfile;   alter system set disk_asynch_io=true scope=spfile; alter database recover managed standby database cancel; shutdown immediate; startup  alter database recover managed standby database parallel 4 disconnect from session using current logfile;          极端情况下DG加快恢复速度===在standby端执行，千万不可在primary端调整 alter system set parallel_execution_message_size=32768 scope=spfile;   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） 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 /