mysql 5.1支援觸發器以及自訂函數介面(UDF)的特性，如果配合libmemcache以及Memcached Functions for MySQL，就能夠實現memcache的自動更新。簡單記錄一下安裝測試步驟。
安裝步驟
- 安裝memcached,這個步驟很簡單，隨處可見
- 安裝mysql server 5.1RC，安裝辦法也很福士，不廢話了
- 編譯libmemcached，解壓後安裝即可
./configure; make; make install
- 編譯Memcached Functions for MySQL，在http://download.tangent.org/找一個最新的版本下載就是，
./configure --with-mysql=/usr/local/mysql/bin/mysql_config --libdir=/usr/local/mysql/lib/mysql/
make
make install
接下來有兩個辦法讓Memcached Functions for MySQL在mysql中生效
- 在mysql的shell中執行memcached_functions_mysql源碼目錄下的sql/install_functions.sql，這會把memcache function作為UDF加入mysql
- 運行memcached_functions_mysql源碼目錄下的utils/install.pl，這是一個perl指令碼，作用同上一條
測試memcache function
以下測試指令碼摘自memcached_functions_mysql的源碼目錄，有興趣可以試試
drop table if exists urls;
create table urls (
id int(3) not null,
url varchar(64) not null default '',
primary key (id)
);
select memc_servers_set('localhost:11211');
select memc_set('urls:sequence', 0);
DELIMITER
DROP TRIGGER IF EXISTS url_mem_insert;
CREATE TRIGGER url_mem_insert
BEFORE INSERT ON urls
FOR EACH ROW BEGIN
SET NEW.id= memc_increment('urls:sequence');
SET @mm= memc_set(concat('urls:',NEW.id), NEW.url);
END
DELIMITER ;
insert into urls (url) values ('http://google.com');
insert into urls (url) values ('http://www.ooso.net/index.php');
insert into urls (url) values ('http://www.ooso.net/');
insert into urls (url) values ('http://slashdot.org');
insert into urls (url) values ('http://mysql.com');
select * from urls;
select memc_get('urls:1');
select memc_get('urls:2');
select memc_get('urls:3');
select memc_get('urls:4');
select memc_get('urls:5');
