【发布时间】：2020-02-13 23:54:18
【问题描述】：
我遇到了一个问题，即我的 MySQL 数据库运行缓慢，因此我决定与mysqltuner.pl 联系，在确定自己在做什么之前，我不想进行任何更改。
我在 Ubuntu 18.04 LTS 服务器上运行 MySQL 5.7。
这是来自 mysqltuner 的回复：
-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 17h 51m 40s (400K q [6.226 qps], 15K conn, TX: 1G, RX: 63M)
[--] Reads / Writes: 98% / 2%
[--] Binary logging is disabled
[--] Physical Memory : 7.8G
[--] Max MySQL memory : 352.4M
[--] Other process memory: 1.6G
[--] Total buffers: 192.0M global + 1.1M per thread (151 max threads)
[--] P_S Max memory usage: 72B
[OK] Maximum reached memory usage: 207.9M (2.61% of installed RAM)
[OK] Maximum possible memory usage: 352.4M (4.43% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[OK] Slow queries: 0% (0/400K)
[OK] Highest usage of available connections: 9% (15/151)
[OK] Aborted connections: 0.01% (1/15256)
[!!] name resolution is active : a reverse name resolution is made for each new connection and can reduce performance
[!!] Query cache may be disabled by default due to mutex contention.
[!!] Query cache efficiency: 0.0% (0 cached / 338K selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 37K sorts)
[!!] Joins performed without indexes: 494
[!!] Temporary tables created on disk: 78% (15K on disk / 20K total)
[OK] Thread cache hit rate: 99% (30 created / 15K connections)
[OK] Table cache hit rate: 29% (1K open / 6K opened)
[OK] Open file limit used: 2% (136/5K)
[OK] Table locks acquired immediately: 100% (1K immediate / 1K locks)
-------- Performance schema ------------------------------------------------------------------------
[--] Memory used by P_S: 72B
[--] Sys schema is installed.
-------- ThreadPool Metrics ------------------------------------------------------------------------
[--] ThreadPool stat is disabled.
-------- MyISAM Metrics ----------------------------------------------------------------------------
[!!] Key buffer used: 18.2% (3M used / 16M cache)
[OK] Key buffer size / total MyISAM indexes: 16.0M/126.0K
[!!] Read Key buffer hit rate: 68.8% (16 cached / 5 reads)
-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 0
[OK] InnoDB File per table is activated
[OK] InnoDB buffer pool / data size: 128.0M/77.4M
[!!] Ratio InnoDB log file size / InnoDB Buffer pool size (75 %): 48.0M * 2/128.0M should be equal 25%
[OK] InnoDB buffer pool instances: 1
[--] Number of InnoDB Buffer Pool Chunk : 1 for 1 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: 99.96% (12403660 hits/ 12408102 total)
[!!] InnoDB Write Log efficiency: 51.81% (14419 hits/ 27833 total)
[OK] InnoDB log waits: 0.00% (0 waits / 13414 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/error.log file
Control error line(s) into /var/log/mysql/error.log file
MySQL started within last 24 hours - recommendations may be inaccurate
Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1
Adjust your join queries to always utilize indexes
When making adjustments, make tmp_table_size/max_heap_table_size equal
Reduce your SELECT DISTINCT queries which have no LIMIT clause
Variables to adjust:
query_cache_size (=0)
query_cache_type (=0)
query_cache_limit (> 1M, or use smaller result sets)
join_buffer_size (> 256.0K, or always use indexes with joins)
tmp_table_size (> 16M)
max_heap_table_size (> 16M)
innodb_log_file_size * innodb_log_files_in_group should be equal to 1/4 of buffer pool size (=64M) if possible.
我所有的网站都在最新版本的 Wordpress 上运行，并且大部分内容都是静态的——比如商业网站。
如何基于mysqltuneranalyze提高MySQL的性能？
【问题讨论】：
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附加信息请求。 # 内核，MySQL 主机服务器上的任何 SSD 或 NVME 设备？在 pastebin.com 上发布并分享链接。从 SSH 登录根，文本结果： B) SHOW GLOBAL STATUS;至少 24 小时正常运行时间后 C) 显示全局变量； D) 显示完整的处理程序； E) 完整的 MySQLTuner 报告和可选的非常有用的信息，如果可用，包括 - htop 或 top 用于大多数活动应用程序，ulimit -a 用于 Linux/Unix 限制列表，iostat -xm 5 3 用于按设备和核心/cpu 计数的 IOPS，为服务器工作负载调优分析提供建议。
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