编辑：这可能是 5.0 特定的错误。（我在 5.0.83）。删除 innodb_log_file_size 设置可以解决问题。这是完全有道理的。不是。
谷歌搜索在 5.0 中发现了一些类似但不相同的问题，这些问题后来被修补。
由于 my.cnf 中的“错误”设置，MySQL 5.0 上的这个 create 语句会给我“指定的密钥太长；最大密钥长度为 1000 字节”。
CREATE TABLE ReproduceTheProblem (
COLUMN_ONE varchar(200) character set utf8 default NULL,
COLUMN_TWO varchar(200) character set utf8 default NULL,
KEY ThisKeyBreaks(COLUMN_ONE, COLUMN_TWO)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
在尝试提高性能时，我发现 my.cnf 设置性能良好但出现“密钥太长”错误。我确实有可以创建此密钥的 my.cnf 设置，但是在将数据导入到另一个非常大的表中时表现非常糟糕。
有效但性能不佳的设置（并且在我尝试拨入不同设置时具有一些奇怪的值）：
[client]
port = 3306
socket = /tmp/mysql.sock
[mysqld]
port = 3306
socket = /tmp/mysql.sock
skip-locking
key_buffer_size = 384M
max_allowed_packet = 1024M
table_cache = 256
max_sp_recursion_depth=255
sort_buffer_size = 2M
read_buffer_size = 2M
read_rnd_buffer_size = 8M
myisam_sort_buffer_size = 64M
myisam_max_sort_file_size = 30G
thread_cache_size = 8
query_cache_size= 16M
thread_concurrency = 8
max_heap_table_size = 9900000
skip-federated
log-bin=mysql-bin
server-id = 1
[mysqldump]
quick
max_allowed_packet = 256M
[mysql]
no-auto-rehash
[isamchk]
key_buffer = 256M
sort_buffer_size = 256M
read_buffer = 2M
write_buffer = 2M
[myisamchk]
key_buffer = 256M
sort_buffer_size = 256M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout
执行良好的设置，但给我密钥长度错误：
[client]
port = 3306
socket = /tmp/mysql.sock
[mysqld]
port = 3306
socket = /tmp/mysql.sock
max_allowed_packet = 200M
table_cache = 256
query_cache_type = 1
query_cache_limit = 20M
query_cache_size = 500M
long_query_time = 2
thread_cache_size = 1000
thread_concurrency = 4
innodb_thread_concurrency = 4
old_passwords = 1
max_connections = 1000
max_sp_recursion_depth = 255
server-id = 0
innodb_buffer_pool_size = 800M
innodb_additional_mem_pool_size = 50M
innodb_log_file_size=50M
innodb_log_buffer_size = 200M
innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout =50
[mysqldump]
quick
max_allowed_packet = 200M
[mysql]
no-auto-rehash