这两天碰到的几个技术问题

1. MySQL5.1导出，然后MySQL5.0导入报错
提示: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'USING BTREE' 云云

bug报告见 http://bugs.mysql.com/bug.php?id=25162

解决方法就是手动修改 foobar.sql 文件，找到报错的那行
一般是类似下行这行的东西

UNIQUE KEY `IDX_BASE` (`entity_type_id`,`entity_id`,`attribute_id`,`store_id`) USING BTREE ,

把 USING BTREE 挪个位置，改成下面这样即可

UNIQUE KEY `IDX_BASE` USING BTREE (`entity_type_id`,`entity_id`,`attribute_id`,`store_id`) ,

2.iredmail 0.6.1在debian lenny上安装postfix-policyd时出错，提示数据库连接失败，用户名root，密码空
除非你的MySQL root密码是空密码，否则一般都会失败的
解决办法就是用apt单独安装postfix-policyd，就会出现要求输入MySQL密码的对话框

3.卸载amavis-new 后重装 amavisd-new 失败
提示

Creating/updating amavis user account...
Broken amavis system user found. To insure data-safety,
it is up to you the local administrator to remove the broken
amavis user, or repair it so that it is sane
dpkg: error processing amavisd-new (--configure):
subprocess post-installation script returned error exit status 1
Errors were encountered while processing:
amavisd-new

原因是 amavisd-new 会创建 amavis 和 amavis组，但卸载的脚本有bug没有删除amavis用户。
userdel amavis 删除 amavis用户

再继续安装即可

bug报告见 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=495629