相对于MYISAM，在插入时使用InnoDB，mysql速度较慢

Question

我刚刚安装了MySQL 5.5，它默认使用InnoDB引擎，但我发现插入查询非常缓慢。关闭general-log后速度有所提升，但仍然很慢。我正在分析MySQL以找出问题所在，但还没有任何进展。

以下是比较结果：

测试一个包含500行的MYISAM表。 - 每秒插入5866个记录。 - 每秒读取128866行记录。 - 每秒更新56306个记录。

测试一个包含500行的INNODB表。 - 每秒插入9个记录。 - 每秒读取28539行记录。 - 每秒更新4358个记录。

在InnoDB中，我只能插入9个查询，而在MyISAM中可以插入5866个查询。

这是我的my.ini配置文件（windows 8 64位）：

[mysql]

default-character-set=utf8
no-auto-rehash

[mysqld]
max_allowed_packet = 500M
table_open_cache = 512

# 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="C:\Program Files\MySQL\MySQL Server 5.5\"

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

# The default character set that will be used when a new schema or table is
# created and no character set is defined
character-set-server=utf8

# 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"

# Enable Windows Authentication
# plugin-load=authentication_windows.dll

# General and Slow logging.
#log-output=FILE
#general-log=0
#general_log_file="POOYA.log"
#slow-query-log=0
#slow_query_log_file="POOYA-slow.log"
#long_query_time=10

#innodb_flush_log_at_trx_commit = 2

# Binary Logging.
# log-bin

# Error Logging.
log-error="POOYA.err"


max_connections=100

query_cache_size=32M

table_cache=512

tmp_table_size=64M

thread_cache_size=8

myisam_max_sort_file_size=100G

myisam_sort_buffer_size=64M

key_buffer_size=256M

# 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=1M
read_rnd_buffer_size=4M

# 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=1M

#*** INNODB Specific options ***
# innodb_data_home_dir=0.0

# 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=64M

# 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=8M

# 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=512M

# 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=49M

# 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=17
[mysqldump]
quick
max_allowed_packet = 16M

[myisamchk]
key_buffer_size = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout

我已经编辑了这个文件以获得更高的性能，而且从未遇到过与mysql 5.1相关的任何问题。

- Pouya Sanooei

---

你应该看一下 innodb_flush_log_at_trx_commit = 0 - 这应该会显著提高速度（编辑，也许2也可以，因为它减轻了磁盘I/O的压力）。 - Najzero

升级到MySQL 5.5或MySQL 5.6怎么样？ - ProfileTwist

我把它改成了2，结果速度飞快地修复了！现在每秒可以插入5615条数据。这么一个小小的改变居然能带来如此巨大的影响，真是让人惊喜不已 :D 非常感谢你的帮助！ - Pouya Sanooei

@Najzero：您可以发布这个答案，这样我就可以将其标记为正确（我不能回答自己的问题，因为声望值不够:/）。 - Pouya Sanooei

你可以分享将innodb_flush_log_at_trx_commit设置为0后的基准测试结果吗？ - Gokul N K

我现在没有相同的操作系统或环境了，但我记得每秒6k个插入。 - Pouya Sanooei

Answer 1

按要求，提交级别的日志记录通常会导致大量磁盘压力，从而极大地降低使用Inno进行MySQL实例数据吞吐量。

将mysql.ini设置为innodb_flush_log_at_trx_commit = 0（或2）通常可以解决此问题。

请注意，ACID规则希望该值为1...

- Najzero

Answer 2

你是一次添加一行吗？

如果您每个事务添加多行，那会很有帮助。

# 1:
INSERT INTO my_table VALUES (1, "A");
INSERT INTO my_table VALUES (2, "B");

# 2:
INSERT INTO my_table VALUES (1, "A"),(2, "B");

# 3:
BEGIN;
INSERT INTO my_table VALUES (1, "A");
INSERT INTO my_table VALUES (2, "B");
COMMIT;

在InnoDB中，#2和#3比#1快得多。

#2也有助于MyISAM，但不如InnoDB。大致数字是，我看到这将MyISAM加速了2倍，而InnoDB加速了100倍。

- Trade-Ideas Philip

Answer 3

您也可以使用以下命令直接在MySQL命令行上进行设置：

SET GLOBAL innodb_flush_log_at_trx_commit = 0;

- Mark Howard