[20170224]测试数据库块在文件系统缓存多少.txt
--//生产系统一个小数据库测试看看缓存多少.
1.安装nocache:
略.
https://github.com/Feh/nocache
2.执行如下:
# find oradata -name *.* -print | xargs -I {} cachestats {}
oradata/xxxxxx/undotbs01.dbf pages in cache: 12902/465922 (2.8%) [filesize=1863688.0K, pagesize=4K]
oradata/xxxxxx/redostb03.rbo pages in cache: 0/12801 (0.0%) [filesize=51200.5K, pagesize=4K]
oradata/xxxxxx/redo01.log pages in cache: 9511/12801 (74.3%) [filesize=51200.5K, pagesize=4K]
oradata/xxxxxx/zzzzzz_his01.dbf pages in cache: 368953/1835010 (20.1%) [filesize=7340040.0K, pagesize=4K]
oradata/xxxxxx/sysaux01.dbf pages in cache: 53541/304642 (17.6%) [filesize=1218568.0K, pagesize=4K]
oradata/xxxxxx/control02.ctl pages in cache: 244/2884 (8.5%) [filesize=11536.0K, pagesize=4K]
oradata/xxxxxx/tsp_audit01.dbf pages in cache: 22/98306 (0.0%) [filesize=393224.0K, pagesize=4K]
oradata/xxxxxx/redostb01.rbo pages in cache: 0/12801 (0.0%) [filesize=51200.5K, pagesize=4K]
oradata/xxxxxx/zzzzzz01.dbf pages in cache: 2706/393218 (0.7%) [filesize=1572872.0K, pagesize=4K]
oradata/xxxxxx/redo02.log pages in cache: 11433/12801 (89.3%) [filesize=51200.5K, pagesize=4K]
oradata/xxxxxx/redostb02.rbo pages in cache: 0/12801 (0.0%) [filesize=51200.5K, pagesize=4K]
oradata/xxxxxx/temp01.dbf pages in cache: 32/425986 (0.0%) [filesize=1703944.0K, pagesize=4K]
oradata/xxxxxx/control01.ctl pages in cache: 2876/2884 (99.7%) [filesize=11536.0K, pagesize=4K]
oradata/xxxxxx/users01.dbf pages in cache: 6/1282 (0.5%) [filesize=5128.0K, pagesize=4K]
oradata/xxxxxx/system01.dbf pages in cache: 15620/258562 (6.0%) [filesize=1034248.0K, pagesize=4K]
oradata/xxxxxx/redo03.log pages in cache: 11428/12801 (89.3%) [filesize=51200.5K, pagesize=4K]
oradata/xxxxxx/redostb04.rbo pages in cache: 0/12801 (0.0%) [filesize=51200.5K, pagesize=4K]
oradata/xxxxxx/zzzzzz_emr01.dbf pages in cache: 166/131074 (0.1%) [filesize=524296.0K, pagesize=4K]
# find oradata -name *.* -print | xargs -I {} cachestats {} | cut -d":" -f2 | cut -d"/" -f1 | sed -e '1,$s/$/+/' -e '$s/+$//' | xargs |bc
489496
--//489496*4096/1024/1024=1912M.
# free -m
total used free shared buffers cached
Mem: 7908 6480 1427 0 323 3922
-/+ buffers/cache: 2234 5673
Swap: 20002 0 20002
3.清除缓存:
# find oradata -name *.* -print | xargs -I {} cachedel {}
# free -m
total used free shared buffers cached
Mem: 7908 4566 3341 0 323 2010
-/+ buffers/cache: 2232 5675
Swap: 20002 0 20002
--//3341-1427=1914,基本接近.
