Memcache�洢һЩҪ��

�� ʱ�䣺2011-03-08 | ��壺�� С��

[��]�� Memcacheʹ��Slab Allocator��ڴ��:��Ԥ�ȹ涨�Ĵ�С��ڴ��ָ��ض��ȵĿ飬��ȫ��ڴ��Ƭ�� Memcache�Ĵ洢�漰��slab��page��chunk�� 1��ChunkΪ�̶��С��ڴ��ռ䣬Ĭ...

��

Memcacheʹ��Slab Allocator��ڴ��:��Ԥ�ȹ涨�Ĵ�С��ڴ��ָ��ض��ȵĿ飬��ȫ��ڴ��Ƭ��

Memcache�Ĵ洢�漰��slab��page��chunk��

1��ChunkΪ�̶��С��ڴ��ռ䣬Ĭ��Ϊ96Byte��

2��page��Ӧʵ�ʵ��ռ䣬1��pageΪ1M��

3��ͬ��С��chunk�ֳ�Ϊslab��

Memcached��ʱ��-n��-f��slab��Ӧ��Memcacheÿ��1page��1M�ռ��ָ��ɸ�chunk��Щchunk��ͬ��Ĵ�С��ͬһ��slab��

��ӡ��ͨ��memcache��item��ʱ��

1�� Memcache��item�Ĵ�С��key+value+flags��,ѡȡ��ʵ�slab��պ��ܷ��¸�item��slab��

2�� item��Ӧ��slabδ��ֹ��1��page��ע�⣬��1M�ռ䲻��Ƿ��ﵽmemcachedʹ��ڴ涼��ɹ��Ӹ�item��slab�е�chunk

3�� item��Ӧ��slab��ֹ��ڸ�slab��ѡ��expired��free_chunks��delete��1.2.2��delete��chunk��Ų��ܱ��ظ��õ��⣩��chunk��д洢��ν�ѡ��δʹ�ù��chunk��free_chunks_end��д洢��

4�� item��Ӧ��slab��ֹ��Ƕ�Ӧ��slab�Ѿ��洢��ˣ��ô��һ��µ�page��page��Ϊ��Ӧ��С��chunk��洢��

5�� item��Ӧ��slab��ֹ��Ƕ�Ӧ��slab�Ѿ��洢��˲��memcacheҲ�ﵽ��ڴ�ʹ�á��ʹ��lru�㷨��item��ܽ�δ��ڵ�item��ʱ��eviction++

��ɾ��

1�� Delete��ֻ�ǽ��chunk��Ϊɾ��״̬��´�ʹ�ý��chunk��

��flush��

1�� Flush��൱�ڽ��е�itemʧЧ��һ��ı�memcache�ڴ��

һЩע��

1. memcache�Ѿ��ڴ治��
2. memcache��ĳ��slab��ڴ�ҳ��ٷ��slab��
3. flush_all��memcache��ڴ�ҳ�ĸ��֣�ֻ�Ǹ��е�item��Ϊ��ڡ�
4. memcache��洢��item(key+value)��С��Ϊ1M��page��С1M��

5��memcache�ķֲ�ʽ�ǿͻ��˳��ͨ��hash�㷨�õ��keyȡģ��ʵ�֣��ͬ��Կ��ܻ��ò�ͬ��hash�㷨��ͬ��Ŀͻ��˳��Ҳ�п��ʹ��ķ��ڶ��ԡ��ģ�鹲��ͬһ��memcached��ʱ��һ��Ҫע��ڿͻ��ѡ��ͬ��hash�㷨

6��memcachedʱ��ͨ��-M��ֹLRU�滻��ڴ��þ�ʱadd��set�᷵��ʧ��

7��memcached��ʱָ��ݴ洢��û�а��ռ�õ��ڴ桢�Լ�Ϊ�˱��ݶ��õĹ��ռ䡣��ռ�õ��ڴ��ʱָ��ڴ��Ҫע�⡣

8��memcache�洢��ʱ��key�ĳ��ƣ�php��C��󳤶ȶ��250

ת��ע��Դ��ITѧϰ�� ַ��http://www.t086.com/ ��Ƽ��
�ر�� վ��ر��ֹת�ص�ר��¿��ת�أ��ע��ԭʼ��ߡ��°�Ȩ��ԭʼ��С��ڱ��վת��µĸ��˺��վ��Ǳ�ʾ��л�⡣��վת�ص��а�Ȩ��ϵ��ǣ��ǻᾡ��Ը��

�� ( memcache �ڴ� �� )

��Ӧ�Բ��(2) - ��ϲ��첽��

Linode��$10��ˣ�1G�ڴ�+24GSSD

PHP��copy on writeдʱ��ƻ��

mysql��ʹ��ʱ��ڴ��ӿ��ٶȣ�

MySQL��ٲ�ѯ�ٶȵĶ��ѯ��

PHP Memcached ��Ӧ��

mysql memcached UDF ��װ��

�˽��Щ�֣�� һ Щ Ҫ ��