Shared pool深入分析及性能调整(三)

SQL> select * from v$sysstat where name in ('parse count (total)','parse count (hard)');
STATISTIC# NAME CLASS VALUE
---------- ------------------ -------- ---------- 
235 parse count (total) 64 4989
236 parse count (hard) 64 993
对于library cache来说，可以使用如下的统计信息来判断，如果reload-to-pins大于0.01，则说明shared pool设置过小，需要增加shared pool。
SQL> select sum(pins) "Executions", sum(reloads) "Cache Misses",
2 sum(reloads)/sum(pins) " reload-to-pins" from v$librarycache;
Executions Cache Misses reload-to-pins
---------- ------------ --------------- 
4458375 4159 0.0009328510948

SQL> select sum(gets) as gets,sum(getmisses) as misses,
2 sum(getmisses)/sum(gets) as miss_ratio from v$rowcache;
GETS MISSES MISS_RATIO
---------- ---------- ---------- 
4762783 15397 0.00323277