莫名奇妙的慢 gc cr block lost

方法论是什么

awr

占比较高，应该是异常

参数设置没有问题

检查统计数据

明显节点2多。

netstat -p udp
no -a|grep udp
receive_space=655360
send_space=65536

sho parameter multib
netstat -s | grep "packet reassembles failed"|awk '{print $1}'

'netstat -s' 或 'netstat -su'，并根据具体平台查看 "udpInOverflowsudpInOverflows", "packet receive errors", "fragments dropped" 或 "outgoing packet drop" 信息

set lin 120
SELECT to_char(sysdate,'yyyy-mm-dd') riqi, a.inst_ID "INSTANCE", A.VALUE "GC BLOCKS LOST",
 B.VALUE "GC CUR BLOCKS SERVED",
 C.VALUE "GC CR BLOCKS SERVED",
 round(A.VALUE/(B.VALUE+C.VALUE+0.01),1) RATIO
 FROM GV$SYSSTAT A, GV$SYSSTAT B, GV$SYSSTAT C
 WHERE A.NAME='gc blocks lost' AND
 B.NAME='gc current blocks served' AND
 C.NAME='gc cr blocks served' and
 B.INST_ID=a.inst_id AND  C.INST_ID = a.inst_id
 order by 2;


select inst_id, event, total_waits,time_waited 
from gv$system_event 
where event in ('gc current block lost','gc cr block lost')
order by inst_id, total_waits desc;

参考：http://blog.chinaunix.net/uid-20687159-id-5861931.html 超乎