Other default tuning values
MySQL Server Instance Configuration File
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Generated by the MySQL Server Instance Configuration Wizard
Installation Instructions
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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 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
Guidelines for editing this file
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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
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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=MYSQL
port=3306
[mysql]
no-beep
default-character-set=
SERVER SECTION
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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=3
[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=“C:/Program Files/MySQL/MySQL Server 8.0/”
Path to the database root
#datadir=C:/ProgramData/MySQL/MySQL Server 8.0/Data
datadir=C:/ProgramData/MySQL/MySQL Server 8.0/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=
The default authentication plugin to be used when connecting to the server
default_authentication_plugin=caching_sha2_password
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_ENGINE_SUBSTITUTION”
General and Slow logging.
log-output=FILE
general-log=0
general_log_file=“LAPTOP-AAR9VK5N.log”
slow-query-log=1
slow_query_log_file=“LAPTOP-AAR9VK5N-slow.log”
long_query_time=10
Binary Logging.
log-bin=“LAPTOP-AAR9VK5N-bin”
Error Logging.
log-error=“LAPTOP-AAR9VK5N.err”
Server Id.
server-id=1
Specifies the on how table names are stored in the metadata.
If set to 0, will throw an error on case-insensitive operative systems
If set to 1, table names are stored in lowercase on disk and comparisons are not case sensitive.
If set to 2, table names are stored as given but compared in lowercase.
This option also applies to database names and table aliases.
NOTE: Modify this value after Server initialization won’t take effect.
lower_case_table_names=1
Secure File Priv.
secure-file-priv=“C:/ProgramData/MySQL/MySQL Server 8.0/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=151
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=12M
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=15M
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=8M
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=29K
read_rnd_buffer_size=256K
#*** INNODB Specific options ***
innodb_data_home_dir=
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=8M
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=17
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
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
The TCP/IP Port the MySQL Server X Protocol will listen on.
loose_mysqlx_port=33060