这是一个完整的windows配置文件，改了group_concat长度和mode的strict选项（否则每个字段都要定义null，不能空），最大使用内存查询：

SELECT

  (

    @@key_buffer_size + @@innodb_buffer_pool_size + @@query_cache_size + @@tmp_table_size + @@max_connections * (

      @@read_buffer_size + @@read_rnd_buffer_size + @@sort_buffer_size + @@join_buffer_size + @@binlog_cache_size + @@thread_stack

    )

  ) / 1024 / 1024 AS result,

  @@read_buffer_size/1024 AS read_buffer_size, 

  @@read_rnd_buffer_size/1024 AS read_rnd_buffer_size, 

  @@sort_buffer_size /1024 AS sort_buffer_size, 

  @@join_buffer_size/1024  AS join_buffer_size, 

  @@binlog_cache_size/1024 AS binlog_cache_size, 

  @@thread_stack/1024 AS thread_stack

注意：有的参数 per connection定义，不能太大

# Other default tuning values

# 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.

#

# For advice on how to change settings please see

# http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html

#

#

# 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]

# pipe

# socket=0.0

port=3306

[mysql]

no-beep

default-character-set=gbk

# 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.

#

# server_type=1

[mysqld]

# The next three options are mutually exclusive to SERVER_PORT below.

# skip-networking

# enable-named-pipe

# shared-memory

# shared-memory-base-name=MYSQL

# The Pipe the MySQL Server will use

# socket=MYSQL

# 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="E:/Mysql57"

# Path to the database root

datadir="E:/Mysql57/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=gbk

# group concat

group_concat_max_len = 256K

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

default-storage-engine=INNODB

# Set the SQL mode to strict

#sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"

sql-mode  = "NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION"

# Enable Windows Authentication

# plugin-load=authentication_windows.dll

# General and Slow logging.

log-output=FILE

general-log=1

general_log_file="JYJ-PC.log"

slow-query-log=1

slow_query_log_file="JYJ-PC-slow.log"

long_query_time=10

# Binary Logging.

# log-bin

# Error Logging.

log-error="JYJ-PC.err"

# Server Id.

server-id=1

# Secure File Priv.

secure-file-priv="E:/Mysql57/Uploads"

# 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=1024

# 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=256M

# 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_open_cache=2000

# 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=345M

# 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=10

#*********************************************************** 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=677M

# 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=128M

# 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=64K

read_rnd_buffer_size=256K

#*** 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

# 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=1M

# 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=1G

# 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=48M

# 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=8

# The increment size (in MB) for extending the size of an auto-extend InnoDB system tablespace file when it becomes full.

innodb_autoextend_increment=64

# The number of regions that the InnoDB buffer pool is divided into.

# For systems with buffer pools in the multi-gigabyte range, dividing the buffer pool into separate instances can improve concurrency,

# by reducing contention as different threads read and write to cached pages.

innodb_buffer_pool_instances=8

# Determines the number of threads that can enter InnoDB concurrently.

innodb_concurrency_tickets=5000

# Specifies how long in milliseconds (ms) a block inserted into the old sublist must stay there after its first access before

# it can be moved to the new sublist.

innodb_old_blocks_time=1000

# It specifies the maximum number of .ibd files that MySQL can keep open at one time. The minimum value is 10.

innodb_open_files=300

# When this variable is enabled, InnoDB updates statistics during metadata statements.

innodb_stats_on_metadata=0

# When innodb_file_per_table is enabled (the default in 5.6.6 and higher), InnoDB stores the data and indexes for each newly created table

# in a separate .ibd file, rather than in the system tablespace.

innodb_file_per_table=1

# Use the following list of values: 0 for crc32, 1 for strict_crc32, 2 for innodb, 3 for strict_innodb, 4 for none, 5 for strict_none.

innodb_checksum_algorithm=0

# The number of outstanding connection requests MySQL can have.

# This option is useful when the main MySQL thread gets many connection requests in a very short time.

# It then takes some time (although very little) for the main thread to check the connection and start a new thread.

# The back_log value indicates how many requests can be stacked during this short time before MySQL momentarily

# stops answering new requests.

# You need to increase this only if you expect a large number of connections in a short period of time.

back_log=80

# If this is set to a nonzero value, all tables are closed every flush_time seconds to free up resources and

# synchronize unflushed data to disk.

# This option is best used only on systems with minimal resources.

flush_time=0

# The minimum size of the buffer that is used for plain index scans, range index scans, and joins that do not use

# indexes and thus perform full table scans.

join_buffer_size=256K

# The maximum size of one packet or any generated or intermediate string, or any parameter sent by the

# mysql_stmt_send_long_data() C API function.

max_allowed_packet=4M

# If more than this many successive connection requests from a host are interrupted without a successful connection,

# the server blocks that host from performing further connections.

max_connect_errors=100

# Changes the number of file descriptors available to mysqld.

# You should try increasing the value of this option if mysqld gives you the error "Too many open files".

open_files_limit=4161

# Set the query cache type. 0 for OFF, 1 for ON and 2 for DEMAND.

query_cache_type=1

# If you see many sort_merge_passes per second in SHOW GLOBAL STATUS output, you can consider increasing the

# sort_buffer_size value to speed up ORDER BY or GROUP BY operations that cannot be improved with query optimization

# or improved indexing.

sort_buffer_size=256K

# The number of table definitions (from .frm files) that can be stored in the definition cache.

# If you use a large number of tables, you can create a large table definition cache to speed up opening of tables.

# The table definition cache takes less space and does not use file descriptors, unlike the normal table cache.

# The minimum and default values are both 400.

table_definition_cache=1400

# Specify the maximum size of a row-based binary log event, in bytes.

# Rows are grouped into events smaller than this size if possible. The value should be a multiple of 256.

binlog_row_event_max_size=8K

# If the value of this variable is greater than 0, a replication slave synchronizes its master.info file to disk.

# (using fdatasync()) after every sync_master_info events.

sync_master_info=10000

# If the value of this variable is greater than 0, the MySQL server synchronizes its relay log to disk.

# (using fdatasync()) after every sync_relay_log writes to the relay log.

sync_relay_log=10000

# If the value of this variable is greater than 0, a replication slave synchronizes its relay-log.info file to disk.

# (using fdatasync()) after every sync_relay_log_info transactions.

sync_relay_log_info=10000

# Load mysql plugins at start."plugin_x ; plugin_y".

# plugin_load

# MySQL server's plugin configuration.

# loose_mysqlx_port=33060