我有一个 CentOS 6.5 VM，内存为16 GB。
我感觉 MySQL 反应非常慢，我运行了 MySQLTuner 脚本，并根据给定的建议如何更改my.cny配置文件改善表现？
以上是MySQL重新启动后2天的结果：
[--] Skipped version check for MySQLTuner script
running supported MySQL version 5.7.17-log
[OK] Operating on 64-bit architecture
-------- Storage Engine Statistics -----------------------------------------------------------------
[--] Status: +ARCHIVE +BLACKHOLE +CSV -FEDERATED +InnoDB +MEMORY +MRG_MYISAM +MyISAM +PERFORMANCE_SCHEMA
[--] Data in InnoDB tables: 111M (Tables: 88)
[OK] Total fragmented tables: 0
-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 1d 20h 44m 5s (178K q [1.111 qps], 20K conn, TX: 260M, RX: 24M)
[--] Reads / Writes: 84% / 16%
[--] Binary logging is enabled (GTID MODE: OFF)
[--] Physical Memory : 15.5G
[--] Max MySQL memory : 76.2G
[--] Other process memory: 40.8M
[--] Total buffers: 10.1G global + 448.2M per thread (151 max threads)
[--] P_S Max memory usage: 72B
[--] Galera GCache Max memory usage: 0B
[!!] Maximum reached memory usage: 19.3G (124.21% of installed RAM)
[!!] Maximum possible memory usage: 76.2G (490.99% of installed RAM)
[!!] Overall possible memory usage with other process exceeded memory
[OK] Slow queries: 0% (0/178K)
[OK] Highest usage of available connections: 13% (21/151)
[OK] Aborted connections: 0.04% (8/20336)
[OK] Query cache is disabled by default due to mutex contention on multiprocessor machines.
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 4K sorts)
[OK] No joins without indexes
[OK] Temporary tables created on disk: 24% (420 on disk / 1K total)
[OK] Thread cache hit rate: 93% (1K created / 20K connections)
[OK] Table cache hit rate: 21% (416 open / 1K opened)
[OK] Open file limit used: 0% (3/1K)
[OK] Table locks acquired immediately: 100% (167 immediate / 167 locks)
[OK] Binlog cache memory access: 100.00% (4605 Memory / 4605 Total)
-------- Performance schema ------------------------------------------------------------------------
[--] Memory used by P_S: 72B
[--] Sys schema is installed.
-------- MyISAM Metrics ----------------------------------------------------------------------------
[!!] Key buffer used: 18.2% (3M used / 16M cache)
[OK] Key buffer size / total MyISAM indexes: 16.0M/43.0K
[!!] Read Key buffer hit rate: 85.5% (62 cached / 9 reads)
-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 0
[OK] InnoDB File per table is activated
[OK] InnoDB buffer pool / data size: 10.0G/111.5M
[OK] InnoDB log file size / InnoDB Buffer pool size: 28.0M * 100/10.0G should be equal 25%
[OK] InnoDB buffer pool instances: 10
[--] Number of InnoDB Buffer Pool Chunk : 80 for 10 Buffer Pool Instance(s)
[OK] Innodb_buffer_pool_size aligned with Innodb_buffer_pool_chunk_size & Innodb_buffer_pool_instances
[OK] InnoDB Read buffer efficiency: 99.99% (41669876 hits/ 41674787 total)
[!!] InnoDB Write Log efficiency: 34.26% (17312 hits/ 50528 total)
[OK] InnoDB log waits: 0.00% (0 waits / 33216 writes)
-------- Replication Metrics -----------------------------------------------------------------------
[--] Galera Synchronous replication: NO
[--] This server is acting as master for 1 server(s).
[--] No replication setup for this server.
-------- Recommendations ---------------------------------------------------------------------------
General recommendations:
Control warning line(s) into /var/log/mysqld-error.log file
Control error line(s) into /var/log/mysqld-error.log file
Reduce your overall MySQL memory footprint for system stability
Dedicate this server to your database for highest performance.
这是我的my.cny
[mysqld]
innodb_buffer_pool_size = 10G
innodb_log_file_size = 28M
innodb_log_files_in_group = 28M
innodb_buffer_pool_instances=10
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
binlog_cache_size = 32M
key_buffer_size = 16M
table_open_cache = 64M
sort_buffer_size = 128M
read_buffer_size = 64M
read_rnd_buffer_size = 128M
join_buffer_size = 128M
myisam_sort_buffer_size = 32M
thread_cache_size = 4
query_cache_size= 32M
query_cache_limit = 1M
log-error=/var/log/mysqld-error.log
pid-file=/var/run/mysqld/mysqld.pid
skip-name-resolve
symbolic-links=0
谢谢!!!
答案 0 :(得分：0)
@ user3659206您的配置请求非常极端。
innodb_log_files_in_group = 28M应为2，默认值
如果你将＃放在接下来的4行前面（所以系统使用默认值）
# sort_buffer_size = 128M
# read_buffer_size = 64M
# read_rnd_buffer_size = 128M
# join_buffer_size = 128M
你会惊讶的。关机/重启后。
使用mysqlcalculator.com查看您当前的配置是否已准备好使用82GB并使用您请求的值。
再次运行mysqltuner以查看内存占用减少 请发布您的新mysqltuner，以便我们都能识别您的进度。