我的 8 核服务器处于恒定负载下，理想时间也是 0。以下是 mysqltuner.pl 脚本的输出。有人能帮忙吗，需要更改哪些参数才能减少负载？
-bash-4.1# ./mysqltuner.pl
>> MySQLTuner 1.7.7 - Major Hayden <[email protected]>
>> 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
Please enter your MySQL administrative login: root
Please enter your MySQL administrative password: [OK] Currently running supported MySQL version 5.1.73
[OK] Operating on 64-bit architecture
-------- Log file Recommendations ------------------------------------------------------------------
[--] Log file: /var/log/mysqld.log(442M)
[OK] Log file /var/log/mysqld.log exists
[OK] Log file /var/log/mysqld.log is readable.
[OK] Log file /var/log/mysqld.log is not empty
[!!] Log file /var/log/mysqld.log is bigger than 32 Mb
[!!] /var/log/mysqld.log contains 1 warning(s).
[!!] /var/log/mysqld.log contains 857631 error(s).
[--] 360 start(s) detected in /var/log/mysqld.log
[--] 1) 180301 15:15:36 [Note] /usr/libexec/mysqld: ready for connections.
[--] 2) 180227 16:44:00 [Note] /usr/libexec/mysqld: ready for connections.
[--] 3) 180222 14:29:14 [Note] /usr/libexec/mysqld: ready for connections.
[--] 4) 180214 12:59:28 [Note] /usr/libexec/mysqld: ready for connections.
[--] 5) 180212 16:17:48 [Note] /usr/libexec/mysqld: ready for connections.
[--] 6) 180212 12:34:39 [Note] /usr/libexec/mysqld: ready for connections.
[--] 7) 180205 11:54:19 [Note] /usr/libexec/mysqld: ready for connections.
[--] 8) 180124 15:32:20 [Note] /usr/libexec/mysqld: ready for connections.
[--] 9) 180124 14:58:11 [Note] /usr/libexec/mysqld: ready for connections.
[--] 10) 171206 18:08:52 [Note] /usr/libexec/mysqld: ready for connections.
[--] 28 shutdown(s) detected in /var/log/mysqld.log
[--] 1) 180301 15:15:34 [Note] /usr/libexec/mysqld: Shutdown complete
[--] 2) 180227 16:43:59 [Note] /usr/libexec/mysqld: Shutdown complete
[--] 3) 180222 14:29:12 [Note] /usr/libexec/mysqld: Shutdown complete
[--] 4) 180214 12:59:26 [Note] /usr/libexec/mysqld: Shutdown complete
[--] 5) 180212 16:17:47 [Note] /usr/libexec/mysqld: Shutdown complete
[--] 6) 180212 12:34:37 [Note] /usr/libexec/mysqld: Shutdown complete
[--] 7) 180205 11:54:18 [Note] /usr/libexec/mysqld: Shutdown complete
[--] 8) 180124 15:32:19 [Note] /usr/libexec/mysqld: Shutdown complete
[--] 9) 180124 14:58:10 [Note] /usr/libexec/mysqld: Shutdown complete
[--] 10) 171206 18:08:51 [Note] /usr/libexec/mysqld: Shutdown complete
-------- Storage Engine Statistics -----------------------------------------------------------------
[--] Status: +CSV +InnoDB +MRG_MYISAM
[--] Data in MyISAM tables: 65G (Tables: 122)
[--] Data in InnoDB tables: 4G (Tables: 621)
[!!] Total fragmented tables: 1
-------- Security Recommendations ------------------------------------------------------------------
[OK] There are no anonymous accounts for any database users
[OK] All database users have passwords assigned
[!!] User 'cdn@localhost' has user name as password.
[!!] There is no basic password file list!
-------- CVE Security Recommendations --------------------------------------------------------------
[--] Skipped due to --cvefile option undefined
-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 20d 21h 19m 50s (6M q [3.409 qps], 13K conn, TX: 8G, RX: 11G)
[--] Reads / Writes: 23% / 77%
[--] Binary logging is disabled
[--] Physical Memory : 3.7G
[--] Max MySQL memory : 449.2M
[--] Other process memory: 514.8M
[--] Total buffers: 34.0M global + 2.7M per thread (151 max threads)
[--] P_S Max memory usage: 0B
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 163.2M (4.36% of installed RAM)
[OK] Maximum possible memory usage: 449.2M (12.01% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[OK] Slow queries: 0% (1K/6M)
[OK] Highest usage of available connections: 31% (47/151)
[OK] Aborted connections: 0.06% (8/13524)
[!!] 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 / 1M selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (7 temp sorts / 8K sorts)
[OK] No joins without indexes
[OK] Temporary tables created on disk: 0% (0 on disk / 119K total)
[!!] Thread cache is disabled
[!!] Table cache hit rate: 3% (64 open / 2K opened)
[OK] Open file limit used: 0% (182/50K)
[OK] Table locks acquired immediately: 99% (7M immediate / 7M 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)
[!!] Key buffer size / total MyISAM indexes: 8.0M/25.3G
[!!] Read Key buffer hit rate: 87.0% (530M cached / 68M reads)
[!!] Write Key buffer hit rate: 69.8% (83M cached / 58M writes)
-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 8
[!!] InnoDB File per table is not activated
[!!] InnoDB buffer pool / data size: 8.0M/4.0G
[!!] Ratio InnoDB log file size / InnoDB Buffer pool size (125 %): 5.0M * 2/8.0M should be equal 25%
[--] InnoDB Buffer Pool Chunk Size not used or defined in your version
[OK] InnoDB Read buffer efficiency: 99.97% (3114982800 hits/ 3115816604 total)
[!!] InnoDB Write Log efficiency: 83.44% (9668047 hits/ 11586898 total)
[!!] InnoDB log waits: 0.01% (107 waits / 1918851 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.
[--] Binlog format: STATEMENT
[--] XA support enabled: ON
Use of uninitialized value in concatenation (.) or string at ./mysqltuner.pl
line 233 (#1)
(W uninitialized) An undefined value was used as if it were already
defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
To suppress this warning assign a defined value to your variables.
To help you figure out what was undefined, perl will try to tell you the
name of the variable (if any) that was undefined. In some cases it cannot
do this, so it also tells you what operation you used the undefined value
in. Note, however, that perl optimizes your program and the operation
displayed in the warning may not necessarily appear literally in your
program. For example, "that $foo" is usually optimized into "that "
. $foo, and the warning will refer to the concatenation (.) operator,
even though there is no . in your program.
[--]
[--]
[--] This is a standalone server
-------- Recommendations ---------------------------------------------------------------------------
General recommendations:
/var/log/mysqld.log is > 32Mb, you should analyze why or implement a rotation log strategy such as logrotate!
Control warning line(s) into /var/log/mysqld.log file
Control error line(s) into /var/log/mysqld.log file
Run OPTIMIZE TABLE to defragment tables for better performance
OPTIMIZE TABLE `tendersinfo_com`.`tenders_archive_new`; -- can free 4628.83363723755 MB
Total freed space after theses OPTIMIZE TABLE : 4628.83363723755 Mb
Set up a Secure Password for user@host ( SET PASSWORD FOR 'user'@'SpecificDNSorIp' = PASSWORD('secure_password'); )
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
Set thread_cache_size to 4 as a starting value
Increase table_open_cache gradually to avoid file descriptor limits
Read this before increasing table_open_cache over 64:
This is MyISAM only table_cache scalability problem, InnoDB not affected.
See more details here: https://bugs.mysql.com/bug.php?id=49177
This bug already fixed in MySQL 5.7.9 and newer MySQL versions.
Beware that open_files_limit (50000) variable
should be greater than table_open_cache (64)
Read this before changing innodb_log_file_size and/or innodb_log_files_in_group:
Variables to adjust:
query_cache_size (=0)
query_cache_type (=0)
query_cache_limit (> 1M, or use smaller result sets)
thread_cache_size (start at 4)
table_open_cache (> 64)
key_buffer_size (> 25.3G)
innodb_file_per_table=ON
innodb_buffer_pool_size (>= 4G) if possible.
innodb_log_file_size should be (=1M) if possible, so InnoDB total log files size equals to 25% of buffer pool size.
innodb_log_buffer_size (>= 1M)
答案1
显然 mysql 不是问题，否则你会看到可怕的指标。查看哪些进程消耗了 CPU（top、vmstat、sar......），以及它是否直接影响数据库最终用户（似乎不在日志中：没有慢查询）。
答案2
您使用 Mysqltuner 的建议来优化表tendersinfo_com。tenders_archive_new;
可以释放 4GB 的碎片表空间。
针对您的 my.cnf-ini [mysqld] 部分的建议（源自您的 mysqltuner 报告）
key_buffer_size=24M # from 8M MyISAM needs more RAM to work well
innodb_buffer_pool_size=2500M # from 8M for 62% of RAM
max_connections=100 # from 151 - 47 max_used_connections
thread_cache_size=100 # from 0 for V8 cap of 100 to reduce threads_created
table_open_cache=500 # from 64 - to support ~750 tables
open_file_limit=5000 # from 50000 - for more reasonable limit
expire_logs_days=30 # from 0 for limited historical logs & v8 default days
query_cache_limit=1K # from 1M conserve RAM and QC not actively used
query_cache_min_res_unit=512 # from 4096 to store more RESULTS if QC ever used
采纳建议后，通过获取更多信息，您将有更多机会改进您的实例。需要认真考虑增加 RAM 可用性。4G 支持 69G 数据是一项了不起的成就！谢谢，MySQL。
答案3
针对 my.cnf-ini [mysqld] 部分的建议
刚刚注意到您大量使用了 MyISAM。
key_cache_age_threshold-64800 # from 300 seconds to reduce key_reads
key_cache_division_limit=50 # from 100 for HOT/WARM cache
key_cache_block_size=16384 # from 1024 to make more space available when aged out