这两天遇Lost connection to MySQL server during query问题

现象：远程连接时出现连接丢失。同时mysql 错误日志抛出：
Number of processes running now: 0
090212 13:59:47 mysqld restarted
090212 13:59:47 [Warning] option 'max_join_size': unsigned value 18446744073709551615 adjusted to 4294967295
090212 13:59:47 [Warning] option 'max_join_size': unsigned value 18446744073709551615 adjusted to 4294967295
InnoDB: The log sequence number in ibdata files does not match

访问一个调数据库页面时，apache error_log 提示
Character set '#24' is not a compiled character set and is not specified in the 'NONEXISTENT/charsets/Index' file
File 'NONEXISTENT/charsets/?.conf' not found (Errcode: 2)
Character set '#24' is not a compiled character set and is not specified in the 'NONEXISTENT/charsets/Index' file
File 'NONEXISTENT/charsets/?.conf' not found (Errcode: 2)
Character set '#24' is not a compiled character set and is not s

[ 源码编译 MySQL 5.0.45 ]

shell> groupadd mysql

shell> useradd -g mysql mysql

shell> tar xzf mysql-5.0.45.tar.gz

shell> cd mysql-5.0.45

shell> CFLAGS="-O3" CXX=gcc CXXFLAGS="-O3 -felide-constructors -fno-exceptions -fno-rtti" ./configure \
--prefix=/usr/local/mysql \
--enable-assembler \
--enable-local-infile \
--with-pthread \
--enable-thread-safe-client \
--with-client-ldflags=-all-static \

[关于多用户环境下MySQL使用]

1. MySQL的性能问题
1.1 首先需要对运行做监测
   1.1.1 my.cnf中开启 mysql-slow ，用mysqldumpslow 输出慢查询结果。
   1.1.2 第三方工具 mytop [ http://jeremy.zawodny.com/mysql/mytop/ ]；实时监测。

1.2 根据监测结果对my.cnf的优化配置
   参考my-huge.cnf

2. MySQL多用户下Database Quota 配额限制问题
   解决方案有多种