【发布时间】：2020-03-31 17:25:30
【问题描述】：
我有一个游戏服务器，MySQL 一直处于 100-200% CPU，我尝试优化查询缓存大小但没有帮助。我有一些“大”表，我猜有超过一百万条记录。我有另一个有 150k 记录的表，我怀疑这是因为它在一分钟内被多次写入和读取。我已经运行了 MySQLTuner，结果如下：
[--] Skipped version check for MySQLTuner script
Please enter your MySQL administrative login: root
Please enter your MySQL administrative password: [!!] Your MySQL version 5.5.62 is EOL software! Upgrade soon!
[OK] Operating on 64-bit architecture
-------- Log file Recommendations ------------------------------------------------------------------
[!!] Log file ./srv.err doesn't exist
-------- Storage Engine Statistics -----------------------------------------------------------------
[--] Status: +CSV +InnoDB +MEMORY +MRG_MYISAM +MyISAM +PERFORMANCE_SCHEMA
[--] Data in MyISAM tables: 1.5G (Tables: 130)
[!!] InnoDB is enabled but isn't being used
[OK] Total fragmented tables: 0
-------- Analysis Performance Metrics --------------------------------------------------------------
[--] innodb_stats_on_metadata: ON
[!!] Stat are updated during querying INFORMATION_SCHEMA.
-------- Security Recommendations ------------------------------------------------------------------
[OK] There are no anonymous accounts for any database users
[OK] All database users have passwords assigned
[!!] User 'root@%' does not specify hostname restrictions.
[!!] There is no basic password file list!
-------- CVE Security Recommendations --------------------------------------------------------------
[--] Skipped due to --cvefile option undefined
-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 90d 23h 30m 41s (639M q [81.385 qps], 955K conn, TX: 102G, RX: 90G)
[--] Reads / Writes: 3% / 97%
[--] Binary logging is disabled
[--] Physical Memory : 12.0G
[--] Max MySQL memory : 583.2M
[--] Other process memory: 0B
[--] Total buffers: 168.0M global + 2.8M per thread (151 max threads)
[--] P_S Max memory usage: 0B
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 349.5M (2.86% of installed RAM)
[OK] Maximum possible memory usage: 583.2M (4.77% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[OK] Slow queries: 0% (107/639M)
[OK] Highest usage of available connections: 43% (66/151)
[OK] Aborted connections: 0.55% (5273/955610)
[!!] 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 / 25M selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (456 temp sorts / 3M sorts)
[OK] No joins without indexes
[!!] Temporary tables created on disk: 35% (2K on disk / 6K total)
[!!] Thread cache is disabled
[OK] Table cache hit rate: 96% (236 open / 245 opened)
[OK] table_definition_cache(400) is upper than number of tables(211)
[OK] Open file limit used: 0% (359/352K)
[OK] Table locks acquired immediately: 99% (632M immediate / 633M locks)
-------- Performance schema ------------------------------------------------------------------------
[--] Performance schema is disabled.
[--] Memory used by P_S: 0B
[--] Sys schema isn't installed.
-------- ThreadPool Metrics ------------------------------------------------------------------------
[--] ThreadPool stat is disabled.
-------- MyISAM Metrics ----------------------------------------------------------------------------
[OK] Key buffer used: 100.0% (8M used / 8M cache)
[OK] Key buffer size / total MyISAM indexes: 8.0M/379.3M
[OK] Read Key buffer hit rate: 99.6% (3B cached / 15M reads)
[!!] Write Key buffer hit rate: 86.2% (77M cached / 66M writes)
-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is disabled.
[!!] InnoDB Storage engine is disabled. InnoDB is the default storage engine
-------- AriaDB Metrics ----------------------------------------------------------------------------
[--] AriaDB is disabled.
-------- TokuDB Metrics ----------------------------------------------------------------------------
[--] TokuDB is disabled.
-------- XtraDB Metrics ----------------------------------------------------------------------------
[--] XtraDB is disabled.
-------- Galera Metrics ----------------------------------------------------------------------------
[--] Galera is disabled.
-------- Replication Metrics -----------------------------------------------------------------------
[--] Galera Synchronous replication: NO
[--] No replication slave(s) for this server.
[--] Binlog format: STATEMENT
[--] XA support enabled: ON
[--] Semi synchronous replication Master: Not Activated
[--] Semi synchronous replication Slave: Not Activated
[--] This is a standalone server
-------- Recommendations ---------------------------------------------------------------------------
General recommendations:
Add skip-innodb to MySQL configuration to disable InnoDB
Restrict Host for 'root'@% to root@SpecificDNSorIp
UPDATE mysql.user SET host ='SpecificDNSorIp' WHERE user='root' AND host ='%'; FLUSH PRIVILEGES;
Enable the slow query log to troubleshoot bad queries
Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1
When making adjustments, make tmp_table_size/max_heap_table_size equal
Reduce your SELECT DISTINCT queries which have no LIMIT clause
Set thread_cache_size to 4 as a starting value
Variables to adjust:
SET innodb_stats_on_metadata = OFF
query_cache_size (=0)
query_cache_type (=0)
query_cache_limit (> 1M, or use smaller result sets)
tmp_table_size (> 16M)
max_heap_table_size (> 16M)
thread_cache_size (start at 4)
你怎么看？我该怎么办？ 配备 Intel Xeon 5570 + 12G RAM + RAID1 中的 2x750GB HDD 的专用服务器
提前致谢。
【问题讨论】：
-
我会尝试分析报告底部列出的建议。
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在服务器上运行 show full processlist。查看那里经常出现的查询并对其进行优化。
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"InnoDB 已启用但未使用" - MyISAM 在高并发环境中表现不佳。切换到 InnoDB。
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A) 尽快切换到 InnoDB。 B) 调整您的 InnoDB 安装并确保将内存分配给 InnoDB 缓冲池。 C) 升级 MySQL，因为新版本的性能明显更好，尤其是与 5.5 相比。 D) 获得更多内存。另一个 64GB 不会破坏银行，它会是几百美元，并且可以改变世界。 E) 如果遇到 IO 问题，请切换到 SSD。
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附加信息请求。 # 核心，MySQL 主机服务器上的任何 SSD 设备。在 pastebin.com 上发布并分享链接。 A) 完整（未编辑）my.cnf 或 my.ini 来自 SSH 登录根，文本结果为：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；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，用于服务器工作负载调整分析提供建议。