Ubuntu | Mysql 服务器 300-750% CPU

Question

我已经尝试了很多东西，现在我正在慢慢转化绝望。

对于我的问题，我已经对MySQL配置做了很多调整， 但不幸的是，我总是回到使用非常高的 CPU 的时间。

多个 MySQL 进程部分在 200-750% CPU / Ram 使用率大约 50% 之间是可以的。

系统信息：

根目录：HP ProLiant DL120 1Gbps / Intel Quad-Core Xeon X3440 - 16GB Ram / Ubuntu Server 操作系统

有 3 个数据库（3 个站点），每个数据库有 16 个表 | DB_1 = 35MB - 560MB DB_2 = - = DB_3 3,4GB

网站已优化（数据库查询/缓存等）|每天每页访问者约 15K/天

root 只运行 Nginx + PHP5-FPM 和 mySQL，所有 8 个处理器都完全过载。

MySQLTuner 版本：

>> MySQLTuner 1.1.1 - Major Hayden <major@mhtx.net>
>> Bug reports, feature requests, and downloads at http://mysqltuner.com/
>> Run with '--help' for additional options and output filtering

-------- General Statistics --------------------------------------------------
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.5.44-0ubuntu0.14.04.1
[OK] Operating on 64-bit architecture

-------- Storage Engine Statistics -------------------------------------------
[--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[--] Data in MyISAM tables: 65K (Tables: 2)
[--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17)
[--] Data in InnoDB tables: 3G (Tables: 44)
[!!] Total fragmented tables: 18

-------- Security Recommendations -------------------------------------------
[OK] All database users have passwords assigned

-------- Performance Metrics -------------------------------------------------
[--] Up for: 4s (991 q [247.750 qps], 73 conn, TX: 8M, RX: 91K)
[--] Reads / Writes: 99% / 1%
[--] Total buffers: 12.5G global + 3.6M per thread (100 max threads)
[OK] Maximum possible memory usage: 12.8G (81% of installed RAM)
[OK] Slow queries: 0% (8/991)
[OK] Highest usage of available connections: 28% (28/100)
[OK] Key buffer size / total MyISAM indexes: 256.0M/120.0K
[!!] Query cache efficiency: 17.8% (155 cached / 873 selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 26 sorts)
[OK] Temporary tables created on disk: 20% (61 on disk / 302 total)
[OK] Thread cache hit rate: 61% (28 created / 73 connections)
[OK] Table cache hit rate: 95% (138 open / 145 opened)
[OK] Open file limit used: 5% (52/1K)
[OK] Table locks acquired immediately: 100% (712 immediate / 712 locks)
[OK] InnoDB data size / buffer pool: 3.4G/7.8G

-------- Recommendations -----------------------------------------------------
General recommendations:
Run OPTIMIZE TABLE to defragment tables for better performance
MySQL started within last 24 hours - recommendations may be inaccurate
Enable the slow query log to troubleshoot bad queries

MySQL 配置我这么频繁改，想不到现在的“my.cnf”：

[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock


[mysqld_safe]
socket  = /var/run/mysqld/mysqld.sock
nice    = 0


[mysqld]
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

bind-address    = 127.0.0.1

# Tunning #

tmp_table_size = 4000M
max_heap_table_size = 4200M
max_connections = 100
max_allowed_packet = 16M

thread_cache_size = 32M
query_cache_size = 512M
query_cache_min_res_unit    = 4K

sort_buffer_size    = 2M
join_buffer_size    = 128K

preload_buffer_size = 32K
key_buffer_size = 256M
read_buffer_size    = 1M
read_rnd_buffer_size    = 256K

low_priority_updates    = 1
concurrent_insert   = ALWAYS


# INNODB #
innodb_log_files_in_group = 2
innodb_log_file_size = 256M
innodb_file_per_table = 1
innodb_buffer_pool_instances = 8
innodb_buffer_pool_size = 8000M

innodb_read_io_threads  = 16
innodb_write_io_threads = 16
innodb_thread_concurrency   = 0


# Logging
log_warnings = 2
log_error = /var/log/mysql/error.log
slow_query_log = 1
slow_query_log_file = /var/log/mysql/mysql-slow.log
long_query_time = 1
log_queries_not_using_indexes = 1
min_examined_row_limit = 20


# Binary Log / Replication
server_id = 1
binlog_cache_size = 1M 
sync_binlog = 8
binlog_format = row
expire_logs_days = 7
max_binlog_size = 128M 
relay-log = /var/log/mysql/slave-relay.log
relay-log-index = /var/log/mysql/slave-relay-log.index 


[mysqldump]
quick
single-transaction
max_allowed_packet = 8M


[mysql]
no_auto_rehash


[myisamchk]
key_buffer = 265M
read_buffer = 8M
write_buffer = 8M


[mysqld_safe]
open-files-limit = 8192
log-error = /var/log/mysql/error.log

!includedir /etc/mysql/conf.d/

key_buffer  = 8M
max_allowed_packet  = 8M
thread_stack    = 192K
thread_cache_size = 4


[mysqldump]
quick
quote-names
max_allowed_packet  = 8M


[mysql]
#no-auto-rehash # faster start of mysql but no tab completition


[isamchk]
key_buffer  = 8M

!includedir /etc/mysql/conf.d/

PROCESSLIST 输出：

mysql> SHOW PROCESSLIST;
+-------+---------+-----------+-------------+---------+------+----------------------+------------------------------------------------------------------------------------------------------+
| Id    | User    | Host      | db          | Command | Time | State                | Info                                                                                                 |
+-------+---------+-----------+-------------+---------+------+----------------------+------------------------------------------------------------------------------------------------------+
|   251 | pb_root | localhost | db_name     | Sleep   |    1 |                      | NULL                                                                                                 |
| 48726 | root    | localhost | NULL        | Query   |    0 | NULL                 | SHOW PROCESSLIST                                                                                     |
| 48775 | pb_root | localhost | db_name     | Sleep   |    0 |                      | NULL                                                                                                 |
| 48838 | ww_root | localhost | db_name     | Query   |    1 | Copying to tmp table | SELECT SQL_CALC_FOUND_ROWS  wp_posts.ID FROM wp_posts  INNER JOIN wp_term_relationships ON (wp_posts |
| 48845 | ww_root | localhost | db_name     | Query   |    0 | Copying to tmp table | SELECT SQL_CALC_FOUND_ROWS  wp_posts.ID FROM wp_posts  INNER JOIN wp_term_relationships ON (wp_posts |
| 48846 | ww_root | localhost | db_name     | Query   |    0 | preparing            | SELECT SQL_CALC_FOUND_ROWS  wp_posts.ID FROM wp_posts  WHERE 1=1  AND (wp_posts.ID NOT IN (          |
| 48847 | ww_root | localhost | db_name     | Sleep   |    0 |                      | NULL                                                                                                 |
| 48854 | pb_root | localhost | db_name     | Sleep   |    1 |                      | NULL                                                                                                 |
| 48735 | pb_root | localhost | db_name     | Sleep   |    0 |                      | NULL                                                                                                 |
| 48878 | ww_root | localhost | db_name     | Query   |    1 | Copying to tmp table | SELECT SQL_CALC_FOUND_ROWS  wp_posts.ID FROM wp_posts  INNER JOIN wp_term_relationships ON (wp_posts |
| 48845 | pb_root | localhost | db_name     | Query   |    0 | Copying to tmp table | SELECT SQL_CALC_FOUND_ROWS  wp_posts.ID FROM wp_posts  INNER JOIN wp_term_relationships ON (wp_posts |
| 48827 | ww_root | localhost | db_name     | Sleep   |    0 |                      | NULL                                                                                                 |

+-------+---------+-----------+-------------+---------+------+----------------------+------------------------------------------------------------------------------------------------------+

我试着让自己解决问题，但不幸的是我现在真的很茫然。

Answer 1

如果对你有帮助，请查看以下备注-

tmp_table_size = 4000M #reduce it to 256M even should be lower but set at this time. Also there should be space in /tmp partiont at least equal or greate to this variable.
max_heap_table_size = 4200M #should be same as tmp_table_size so set it 256M
max_connections = 100
max_allowed_packet = 16M 

thread_cache_size = 32M #It should be in numbers set it to 50 for re-use.
query_cache_size = 512M #as your mysql tuner report is showing very less use of query_cache so you can disable it or reduce to 20M
query_cache_limit = 2M #add it if use above query_cache_size variable else no need. 
query_cache_min_res_unit    = 4K #can comment it.

sort_buffer_size    = 2M
join_buffer_size    = 128K

preload_buffer_size = 32K #can comment it for testing.
key_buffer_size = 256M #keep it 50M if not using myisam tables and your server is innodb.
read_buffer_size    = 1M
read_rnd_buffer_size    = 256K

low_priority_updates    = 1 #comment it for testing purpose further you can on as per your requirement.
concurrent_insert   = ALWAYS 


# INNODB #
innodb_log_files_in_group = 2
innodb_log_file_size = 256M  #this can create increase mysql restart time, for mysql 5.5 it is default 5M so you can set as per requirement but 256M is seems too high means you are allocating 500M to log file.
innodb_file_per_table = 1
innodb_buffer_pool_instances = 8
innodb_buffer_pool_size = 8000M

innodb_read_io_threads  = 16
innodb_write_io_threads = 16
innodb_thread_concurrency   = 0

# Binary Log / Replication
binlog_cache_size = 1M #comment it and keep default as it uses server resources per connection if not set it high due to any specific reason.

除了这么多部分在您的配置文件中重复，例如 mysqld_safe 和 mysqldump。

mysqltuner 报告还显示 20% 的临时表正在磁盘上创建，这意味着查询未优化或未使用索引。

需要检查慢查询并优化它们。

根据我的经验，SQL_CALC_FOUND_ROWS 会影响性能，因此您应该使用 count 而不是这个。