下面的内容那个来自Jeff Dean在LADIS大会上做的报告.
Designs,Lessons and Advice from Building Large Distributed Systems
Numbers Everyone Should Know
devices
latency
L1 cache reference
0.5 ns
Branch mispredict
5 ns
L2 cache reference
7 ns
Mutex lock/unlock
25 ns
Main memory reference
100 ns
Compress 1K bytes with Zippy
3,000 ns
Send 2K bytes over 1 Gbps network
20,000 ns
Read 1 MB sequentially from memory
250,000 ns
Round trip within same datacenter [...]
前一天通过duplicate active database 创建好standby之后,,今天简单的测试了一下active standby的apply 效率..
1. 准备工作, 将standby以active standby模式启动.
–Oracle文档要求standby logfile的数量至少比online logfile多一组. 所以我们在此创建4组standby logfile.
alter database add standby logfile group 4 (‘+data’) size 50m;
alter database add standby logfile group 5 (‘+data’) size 50m;
alter database add standby logfile group 6 (‘+data’) size 50m;
alter database add standby logfile group 7 (‘+data’) size 50m;
–将重启standby,并以active standby模式打开.
shutdown immediate;
startup mount;
alter database open read [...]
最近评论