Currently have a MySQL database and experiencing an issue with MySQL running at 600% of the CPU usage.
How to reduce CPU usage? Changes to be made in the my.cnf file?
Specs: 2.3 GHz Intel Xeon® E5-2686 v4 (Broadwell) processors or 2.4 GHz Intel Xeon® E5-2676 v3 (Haswell) processors
8 vCPU's
32GB of RAM
100GB Hard Drive.
Instance is currently hosted with AWS, running Ubuntu 14.04.4 LTS and MySQL version 5.6.33-0ubuntu0.14.04.1-log.
Please see below my.cnf configuration:
# The MySQL database server configuration file.
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
# This will be passed to all mysql clients
# It has been reported that passwords should be enclosed with ticks/quotes
# escpecially if they contain "#" chars...
# Remember to edit /etc/mysql/debian.cnf when changing the socket location.
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
# Here is entries for some specific programs
# The following values assume you have at least 32M ram
# This was formally known as [safe_mysqld]. Both versions are currently parsed.
[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0
log_error=/var/log/mysql/mysql_error.log
[mysqld]
#
# * Basic Settings
#
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking
innodb_io_capacity = 2000
innodb_read_io_threads = 64
innodb_thread_concurrency = 0
innodb_write_io_threads = 64
innodb_buffer_pool_size = 2G
innodb_log_file_size = 1G
# Skip reverse DNS lookup of clients
skip-name-resolve
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address = 127.0.0.1
#
# * Fine Tuning
#
key_buffer = 11G
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover = BACKUP
#max_connections = 100
#table_cache = 64
#thread_concurrency = 10
#
# * Query Cache Configuration
#
query_cache_limit = 1M
query_cache_size = 16M
query_cache_type = 0
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# As of 5.1 you can enable the log at runtime!
general_log_file = /var/log/mysql/mysql.log
general_log = 1
#
# Error log - should be very few entries.
#
log_error = /var/log/mysql/mysql_error.log
#
# Here you can see queries with especially long duration
#log_slow_queries = /var/log/mysql/mysql-slow.log
#long_query_time = 2
#log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
# other settings you may need to change.
#server-id = 1
#log_bin = /var/log/mysql/mysql-bin.log
expire_logs_days = 10
max_binlog_size = 100M
#binlog_do_db = include_database_name
#binlog_ignore_db = include_database_name
#
# * InnoDB
#
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!
#
# * Security Features
#
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
#
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
#
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
[mysql]
#no-auto-rehash # faster start of mysql but no tab completition
[isamchk]
key_buffer = 512M
#
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/
MySQLTuner output:
>> MySQLTuner 1.7.0 - Major Hayden <major@mhtx.net>
>> Bug reports, feature requests, and downloads at http://mysqltuner.com/
>> Run with '--help' for additional options and output filtering
[--] Skipped version check for MySQLTuner script
[OK] Logged in using credentials from debian maintenance account.
[OK] Currently running supported MySQL version 5.6.33-0ubuntu0.14.04.1
[OK] Operating on 64-bit architecture
-------- Log file Recommendations ------------------------------------------------------------------
[--] Log file: /var/log/mysql/mysql_error.log(970K)
[OK] Log file /var/log/mysql/mysql_error.log exists
[OK] Log file /var/log/mysql/mysql_error.log is readable.
[OK] Log file /var/log/mysql/mysql_error.log is not empty
[OK] Log file /var/log/mysql/mysql_error.log is smaller than 32 Mb
[!!] /var/log/mysql/mysql_error.log contains 99 warning(s).
[!!] /var/log/mysql/mysql_error.log contains 4175 error(s).
[--] 24 start(s) detected in /var/log/mysql/mysql_error.log
[--] 1) 2017-02-24 19:42:32 2345 [Note] /usr/sbin/mysqld: ready for connections.
[--] 2) 2017-02-24 19:36:18 1132 [Note] /usr/sbin/mysqld: ready for connections.
[--] 3) 2017-02-24 19:27:45 29185 [Note] /usr/sbin/mysqld: ready for connections.
[--] 4) 2017-02-24 18:03:03 21178 [Note] /usr/sbin/mysqld: ready for connections.
[--] 5) 2017-02-24 17:51:50 19525 [Note] /usr/sbin/mysqld: ready for connections.
[--] 6) 2017-02-24 17:42:33 18098 [Note] /usr/sbin/mysqld: ready for connections.
[--] 7) 2017-02-24 17:34:56 17246 [Note] /usr/sbin/mysqld: ready for connections.
[--] 8) 2017-02-24 11:19:30 16031 [Note] /usr/sbin/mysqld: ready for connections.
[--] 9) 2017-02-24 09:12:46 28867 [Note] /usr/sbin/mysqld: ready for connections.
[--] 10) 2017-02-24 04:53:33 4854 [Note] /usr/sbin/mysqld: ready for connections.
[--] 65 shutdown(s) detected in /var/log/mysql/mysql_error.log
[--] 1) 2017-02-24 19:42:31 1132 [Note] /usr/sbin/mysqld: Shutdown complete
[--] 2) 2017-02-24 19:35:35 29185 [Note] /usr/sbin/mysqld: Shutdown complete
[--] 3) 2017-02-24 19:27:36 21178 [Note] /usr/sbin/mysqld: Shutdown complete
[--] 4) 2017-02-24 18:03:01 19525 [Note] /usr/sbin/mysqld: Shutdown complete
[--] 5) 2017-02-24 17:51:32 18098 [Note] /usr/sbin/mysqld: Shutdown complete
[--] 6) 2017-02-24 17:42:32 17246 [Note] /usr/sbin/mysqld: Shutdown complete
[--] 7) 2017-02-24 17:34:55 16031 [Note] /usr/sbin/mysqld: Shutdown complete
[--] 8) 2017-02-24 11:19:28 15845 [Note] /usr/sbin/mysqld: Shutdown complete
[--] 9) 2017-02-24 11:19:25 15659 [Note] /usr/sbin/mysqld: Shutdown complete
[--] 10) 2017-02-24 11:19:22 15473 [Note] /usr/sbin/mysqld: Shutdown complete
-------- Storage Engine Statistics -----------------------------------------------------------------
[--] Status: +ARCHIVE +BLACKHOLE +CSV -FEDERATED +InnoDB +MEMORY +MRG_MYISAM +MyISAM +PERFORMANCE_SCHEMA
[--] Data in InnoDB tables: 1G (Tables: 262)
[--] Data in MyISAM tables: 137K (Tables: 28)
[!!] Total fragmented tables: 1
-------- Security Recommendations ------------------------------------------------------------------
[OK] There are no anonymous accounts for any database users
[OK] All database users have passwords assigned
[!!] There is no basic password file list!
-------- CVE Security Recommendations --------------------------------------------------------------
[--] Skipped due to --cvefile option undefined
-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 1h 29m 57s (158K q [29.435 qps], 6K conn, TX: 393M, RX: 49M)
[--] Reads / Writes: 77% / 23%
[--] Binary logging is disabled
[--] Physical Memory : 31.4G
[--] Max MySQL memory : 5.1G
[--] Other process memory: 113.0M
[--] Total buffers: 4.5G global + 1.1M per thread (151 max threads)
[--] P_S Max memory usage: 403M
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 5.0G (15.83% of installed RAM)
[OK] Maximum possible memory usage: 5.1G (16.22% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[OK] Slow queries: 0% (0/158K)
[OK] Highest usage of available connections: 21% (32/151)
[!!] Aborted connections: 4.62% (299/6466)
[OK] Query cache is disabled by default due to mutex contention on multiprocessor machines.
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 61K sorts)
[OK] No joins without indexes
[OK] Temporary tables created on disk: 0% (0 on disk / 1K total)
[OK] Thread cache hit rate: 90% (588 created / 6K connections)
[OK] Table cache hit rate: 94% (123 open / 130 opened)
[OK] Open file limit used: 0% (18/5K)
[OK] Table locks acquired immediately: 100% (145K immediate / 145K locks)
-------- Performance schema ------------------------------------------------------------------------
[--] Memory used by P_S: 403.9M
[--] Sys schema isn't installed.
-------- ThreadPool Metrics ------------------------------------------------------------------------
[--] ThreadPool stat is disabled.
-------- MyISAM Metrics ----------------------------------------------------------------------------
[!!] Key buffer used: 18.2% (97M used / 536M cache)
[OK] Key buffer size / total MyISAM indexes: 512.0M/191.0K
[!!] Read Key buffer hit rate: 25.0% (4 cached / 3 reads)
-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 0
[OK] InnoDB File per table is activated
[OK] InnoDB buffer pool / data size: 4.0G/1.1G
[OK] InnoDB log file size / InnoDB Buffer pool size: 512.0M * 2/4.0G should be equal 25%
[!!] InnoDB buffer pool instances: 8
[--] InnoDB Buffer Pool Chunk Size not used or defined in your version
[OK] InnoDB Read buffer efficiency: 100.00% (3052068189 hits/ 3052070121 total)
[!!] InnoDB Write Log efficiency: 63.45% (12468 hits/ 19649 total)
[OK] InnoDB log waits: 0.00% (0 waits / 32117 writes)
-------- AriaDB Metrics ----------------------------------------------------------------------------
[--] AriaDB is disabled.
-------- TokuDB Metrics ----------------------------------------------------------------------------
[--] TokuDB is disabled.
-------- XtraDB Metrics ----------------------------------------------------------------------------
[--] XtraDB is disabled.
-------- RocksDB Metrics ---------------------------------------------------------------------------
[--] RocksDB is disabled.
-------- Spider Metrics ----------------------------------------------------------------------------
[--] Spider is disabled.
-------- Connect Metrics ---------------------------------------------------------------------------
[--] Connect is disabled.
-------- Galera Metrics ----------------------------------------------------------------------------
[--] Galera is disabled.
-------- Replication Metrics -----------------------------------------------------------------------
[--] Galera Synchronous replication: NO
[--] No replication slave(s) for this server.
[--] This is a standalone server.
-------- Recommendations ---------------------------------------------------------------------------
General recommendations:
Control warning line(s) into /var/log/mysql/mysql_error.log file
Control error line(s) into /var/log/mysql/mysql_error.log file
Run OPTIMIZE TABLE to defragment tables for better performance
OPTIMIZE TABLE miwifi.wireless_sessions; -- can free 1791 MB
Total freed space after theses OPTIMIZE TABLE : 1791 Mb
MySQL started within last 24 hours - recommendations may be inaccurate
Reduce or eliminate unclosed connections and network issues
Consider installing Sys schema from https://github.com/mysql/mysql-sys
Variables to adjust:
innodb_buffer_pool_instances(=4)
Best Answer
First of all, on 32Gb machine You give for InnoDB (which I hope You use primary, if not - time to start :-) )
change it for
than after this look at loading again high cpu loading normally come from a lot of sorting operations
You must identify them by total number of executions, and profile individually. It normally not too much, often 10-20 different queries kill 99% of server performance