大型系统的 MySQL 配置文件

Question

我们在 Windows 2003 Server Enterprise Edition 机器上运行 MySQL。 MySQL 是唯一在机器上运行的程序。我们有大约。 8 个从站复制到它，但我的理解是，让多个从站连接到同一个主站不会显着降低性能（如果有的话）。主服务器具有 16G RAM、RAID 10 中的 10 TB 驱动器和四个双核处理器。从我在其他网站上看到的情况来看，我们有一台非常强大的机器作为我们的主数据库服务器。我们刚刚从一台只有 4G RAM 的机器升级，但具有类似的硬盘驱动器、RAID 等。它还在上面运行 Apache，所以它是我们的数据库服务器和应用程序服务器。它变得有点慢，所以我们将数据库服务器拆分到这台新机器上，并将应用程序服务器保留在第一台机器上。我们还将应用程序负载分布在几个其他从属服务器之间，这些从属服务器也运行该应用程序。问题是新的数据库服务器的 mysqld.exe 几乎一直消耗 95-100% 的 CPU，并且确实导致应用程序运行缓慢。我知道我们有几个查询和表结构可以更好地优化，但由于它们在旧的、较小的服务器上工作正常，我假设我们的 my.ini（MySQL 配置）文件没有正确配置。我在网上看到的大部分内容都是在小型机器上设置配置文件，所以任何人都可以帮助我为像我们这样的大型专用机器获取正确的 my.ini 文件吗？我只是不明白 mysqld 怎么会陷入如此困境！

仅供参考：我们每秒大约有 100 个查询。我们只使用MyISAM表，所以在ini文件中设置了skip-innodb。是的，我知道它正在正确读取 ini 文件，因为我可以更改一些设置（例如服务器 ID，它会在启动时杀死服务器）。

这是 my.ini 文件：

#MySQL Server Instance Configuration File
# ----------------------------------------------------------------------
# Generated by the MySQL Server Instance Configuration Wizard
#
#
# Installation Instructions
# ----------------------------------------------------------------------
#
# On Linux you can copy this file to /etc/my.cnf to set global options,
# mysql-data-dir/my.cnf to set server-specific options
# (@localstatedir@ for this installation) or to
# ~/.my.cnf to set user-specific options.
#
# On Windows you should keep this file in the installation directory 
# of your server (e.g. C:\Program Files\MySQL\MySQL Server X.Y). To
# make sure the server reads the config file use the startup option 
# "--defaults-file". 
#
# To run run the server from the command line, execute this in a 
# command line shell, e.g.
# mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
#
# To install the server as a Windows service manually, execute this in a 
# command line shell, e.g.
# mysqld --install MySQLXY --defaults-file="C:\Program Files\MySQL\MySQL Server     X.Y\my.ini"
#
# And then execute this in a command line shell to start the server, e.g.
# net start MySQLXY
#
#
# Guildlines for editing this file
# ----------------------------------------------------------------------
#
# In this file, you can use all long options that the program supports.
# If you want to know the options a program supports, start the program
# with the "--help" option.
#
# More detailed information about the individual options can also be
# found in the manual.
#
#
# CLIENT SECTION
# ----------------------------------------------------------------------
#
# The following options will be read by MySQL client applications.
# Note that only client applications shipped by MySQL are guaranteed
# to read this section. If you want your own MySQL client program to
# honor these values, you need to specify it as an option during the
# MySQL client library initialization.
#
[client]

port=3306

[mysql]

default-character-set=latin1


# SERVER SECTION
# ----------------------------------------------------------------------
#
# The following options will be read by the MySQL Server. Make sure that
# you have installed the server correctly (see above) so it reads this 
# file.
#
[mysqld]

# The TCP/IP Port the MySQL Server will listen on
port=3306


#Path to installation directory. All paths are usually resolved relative to this.
basedir="D:/MySQL/"

#Path to the database root
datadir="D:/MySQL/data"

# The default character set that will be used when a new schema or table is
# created and no character set is defined
default-character-set=latin1

# The default storage engine that will be used when create new tables when
default-storage-engine=MYISAM

# Set the SQL mode to strict
#sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
# we changed this because there are a couple of queries that can get blocked otherwise
sql-mode=""

#performance configs
skip-locking
max_allowed_packet = 1M
table_open_cache = 512

# The maximum amount of concurrent sessions the MySQL server will
# allow. One of these connections will be reserved for a user with
# SUPER privileges to allow the administrator to login even if the
# connection limit has been reached.
max_connections=1510

# Query cache is used to cache SELECT results and later return them
# without actual executing the same query once again. Having the query
# cache enabled may result in significant speed improvements, if your
# have a lot of identical queries and rarely changing tables. See the
# "Qcache_lowmem_prunes" status variable to check if the current value
# is high enough for your load.
# Note: In case your tables change very often or if your queries are
# textually different every time, the query cache may result in a
# slowdown instead of a performance improvement.
query_cache_size=168M

# The number of open tables for all threads. Increasing this value
# increases the number of file descriptors that mysqld requires.
# Therefore you have to make sure to set the amount of open files
# allowed to at least 4096 in the variable "open-files-limit" in
# section [mysqld_safe]
table_cache=3020

# Maximum size for internal (in-memory) temporary tables. If a table
# grows larger than this value, it is automatically converted to disk
# based table This limitation is for a single table. There can be many
# of them.
tmp_table_size=30M


# How many threads we should keep in a cache for reuse. When a client
# disconnects, the client's threads are put in the cache if there aren't
# more than thread_cache_size threads from before.  This greatly reduces
# the amount of thread creations needed if you have a lot of new
# connections. (Normally this doesn't give a notable performance
# improvement if you have a good thread implementation.)
thread_cache_size=64

#*** MyISAM Specific options

# The maximum size of the temporary file MySQL is allowed to use while
# recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
# If the file-size would be bigger than this, the index will be created
# through the key cache (which is slower).
myisam_max_sort_file_size=100G

# If the temporary file used for fast index creation would be bigger
# than using the key cache by the amount specified here, then prefer the
# key cache method.  This is mainly used to force long character keys in
# large tables to use the slower key cache method to create the index.
myisam_sort_buffer_size=64M

# Size of the Key Buffer, used to cache index blocks for MyISAM tables.
# Do not set it larger than 30% of your available memory, as some memory
# is also required by the OS to cache rows. Even if you're not using
# MyISAM tables, you should still set it to 8-64M as it will also be
# used for internal temporary disk tables.
key_buffer_size=3072M

# Size of the buffer used for doing full table scans of MyISAM tables.
# Allocated per thread, if a full scan is needed.
read_buffer_size=2M
read_rnd_buffer_size=8M

# This buffer is allocated when MySQL needs to rebuild the index in
# REPAIR, OPTIMZE, ALTER table statements as well as in LOAD DATA INFILE
# into an empty table. It is allocated per thread so be careful with
# large settings.
sort_buffer_size=2M


#*** INNODB Specific options ***
innodb_data_home_dir="D:/MySQL InnoDB Datafiles/"

# Use this option if you have a MySQL server with InnoDB support enabled
# but you do not plan to use it. This will save memory and disk space
# and speed up some things.
skip-innodb

# Additional memory pool that is used by InnoDB to store metadata
# information.  If InnoDB requires more memory for this purpose it will
# start to allocate it from the OS.  As this is fast enough on most
# recent operating systems, you normally do not need to change this
# value. SHOW INNODB STATUS will display the current amount used.
innodb_additional_mem_pool_size=11M

# If set to 1, InnoDB will flush (fsync) the transaction logs to the
# disk at each commit, which offers full ACID behavior. If you are
# willing to compromise this safety, and you are running small
# transactions, you may set this to 0 or 2 to reduce disk I/O to the
# logs. Value 0 means that the log is only written to the log file and
# the log file flushed to disk approximately once per second. Value 2
# means the log is written to the log file at each commit, but the log
# file is only flushed to disk approximately once per second.
innodb_flush_log_at_trx_commit=1

# The size of the buffer InnoDB uses for buffering log data. As soon as
# it is full, InnoDB will have to flush it to disk. As it is flushed
# once per second anyway, it does not make sense to have it very large
# (even with long transactions).
innodb_log_buffer_size=6M

# InnoDB, unlike MyISAM, uses a buffer pool to cache both indexes and
# row data. The bigger you set this the less disk I/O is needed to
# access data in tables. On a dedicated database server you may set this
# parameter up to 80% of the machine physical memory size. Do not set it
# too large, though, because competition of the physical memory may
# cause paging in the operating system.  Note that on 32bit systems you
# might be limited to 2-3.5G of user level memory per process, so do not
# set it too high.
innodb_buffer_pool_size=500M

# Size of each log file in a log group. You should set the combined size
# of log files to about 25%-100% of your buffer pool size to avoid
# unneeded buffer pool flush activity on log file overwrite. However,
# note that a larger logfile size will increase the time needed for the
# recovery process.
innodb_log_file_size=100M

# Number of threads allowed inside the InnoDB kernel. The optimal value
# depends highly on the application, hardware as well as the OS
# scheduler properties. A too high value may lead to thread thrashing.
innodb_thread_concurrency=10


#replication settings (this is the master)
log-bin=log
server-id = 1

感谢您的所有帮助。非常感谢。

Answer 1

我在 ServerFault 上得到了一些很好的回应。事实证明，主要问题在于新服务器上的磁盘 I/O。 I/O 明显少于旧的 32 位机器，所以我现在正在跟踪它。谢谢。