MySQL性能指标及计算方法
2020-07-25 本文已影响0人
程序员面试吧
绝大多数MySQL性能指标可以通过以下两种方式获取：
（1）mysqladmin
使用mysqladmin extended-status命令获得的MySQL的性能指标，默认为累计值。如果想了解当前状态，需要进行差值计算；加上参数 --relative(-r)，就可以看到各个指标的差值，配合参数--sleep(-i)就可以指定刷新的频率。
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（2）Show global status
可以列出MySQL服务器运行各种状态值，累计值。
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mysqladmin extended-status命令及show global status得到的指标项特别多。实际应用中，重点关注以下性能指标：
tps/qps
tps: Transactions Per Second，每秒事务数；
qps: Queries Per Second每秒查询数；
通常有两种方法计算tps/qps：
方法1：
基于 com_commit、com_rollback 计算tps，基于 questions 计算qps。
TPS = Com_commit/s + Com_rollback/s
其中，
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n20" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">Com_commit /s= mysqladmin extended-status --relative --sleep=1|grep -w Com_commit
Com_rollback/s = mysqladmin extended-status --relative --sleep=1|grep -w Com_rollback
QPS 是指MySQL Server 每秒执行的Query总量，通过Questions (客户的查询数目)状态值每秒内的变化量来近似表示，所以有：
QPS = mysqladmin extended-status --relative --sleep=1|grep -w Questions</pre>
仿照上面的方法还可以得到，mysql每秒select、insert、update、delete的次数等，如：
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n22" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">Com_select/s = mysqladmin extended-status --relative --sleep=1|grep -w Com_select
Com_select/s：平均每秒select语句执行次数
Com_insert/s：平均每秒insert语句执行次数
Com_update/s：平均每秒update语句执行次数
Com_delete/s：平均每秒delete语句执行次数</pre>
方法2:
基于com_%计算tps ,qps
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n25" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">tps= Com_insert/s + Com_update/s + Com_delete/s
qps=Com_select/s + Com_insert/s + Com_update/s + Com_delete/s</pre>
线程状态
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n27" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">* threads_running：
当前正处于激活状态的线程个数
* threads_connected：
当前连接的线程的个数
### 流量状态
* Bytes_received/s：
平均每秒从所有客户端接收到的字节数，单位KB
* Bytes_sent/s：
平均每秒发送给所有客户端的字节数，单位KB</pre>
innodb文件读写次数
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n29" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">* innodb_data_reads：
innodb平均每秒从文件中读取的次数
* innodb_data_writes：
innodb平均每秒从文件中写入的次数
* innodb_data_fsyncs：
innodb平均每秒进行fsync()操作的次数</pre>
innodb读写量
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n31" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">* innodb_data_read：
innodb平均每秒钟读取的数据量，单位为KB
* innodb_data_written：
innodb平均每秒钟写入的数据量，单位为KB</pre>
innodb缓冲池状态
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n33" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">* innodb_buffer_pool_reads:
平均每秒从物理磁盘读取页的次数
* innodb_buffer_pool_read_requests:
平均每秒从innodb缓冲池的读次数（逻辑读请求数）
* innodb_buffer_pool_write_requests:
平均每秒向innodb缓冲池的写次数
* innodb_buffer_pool_pages_dirty:
平均每秒innodb缓存池中脏页的数目
* innodb_buffer_pool_pages_flushed:
* innodb_buffer_read_hit_ratio = ( 1 - Innodb_buffer_pool_reads/Innodb_buffer_pool_read_requests) * 100
innodb缓冲池的读命中率
* Innodb_buffer_usage = ( 1 - Innodb_buffer_pool_pages_free / Innodb_buffer_pool_pages_total) * 100
Innodb缓冲池的利用率</pre>
innodb日志
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n35" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">innodb_os_log_fsyncs:
平均每秒向日志文件完成的fsync()写数量
innodb_os_log_written:
平均每秒写入日志文件的字节数
innodb_log_writes:
平均每秒向日志文件的物理写次数
innodb_log_write_requests:
平均每秒日志写请求数</pre>
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innodb行
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n38" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">innodb_rows_deleted:
平均每秒从innodb表删除的行数
innodb_rows_inserted:
平均每秒从innodb表插入的行数
innodb_rows_read:
平均每秒从innodb表读取的行数
innodb_rows_updated:
平均每秒从innodb表更新的行数
innodb_row_lock_waits:
一行锁定必须等待的时间数
innodb_row_lock_time:
行锁定花费的总时间，单位毫秒
innodb_row_lock_time_avg:
行锁定的平均时间，单位毫秒</pre>
MyISAM读写次数
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n40" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">key_read_requests:
MyISAM平均每秒钟从缓冲池中的读取次数
Key_write_requests:
MyISAM平均每秒钟从缓冲池中的写入次数
key_reads :
MyISAM平均每秒钟从硬盘上读取的次数
key_writes :
MyISAM平均每秒钟从硬盘上写入的次数</pre>
MyISAM缓冲池
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n42" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">MyISAM平均每秒key buffer利用率
Key_usage_ratio =Key_blocks_used/(Key_blocks_used+Key_blocks_unused)*100
MyISAM平均每秒key buffer读命中率
Key_read_hit_ratio=(1-Key_reads/Key_read_requests)*100
MyISAM平均每秒key buffer写命中率
Key_write_hit_ratio =(1-Key_writes/Key_write_requests)*100</pre>
临时表
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n44" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">Created_tmp_disk_tables:
服务器执行语句时在硬盘上自动创建的临时表的数量
Created_tmp_tables:
服务器执行语句时自动创建的内存中的临时表的数量
Created_tmp_disk_tables/Created_tmp_tables比值最好不要超过10%，如果Created_tmp_tables值比较大，可能是排序句子过多或者连接句子不够优化</pre>
其他
<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="bash" cid="n46" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">slow_queries:
执行时间超过long_query_time秒的查询的个数（重要）
sort_rows:
已经排序的行数
open_files:
打开的文件的数目
open_tables:
当前打开的表的数量
select_scan:
对第一个表进行完全扫描的联接的数量</pre>
此外，还有一些性能指标不能通过mysqladmin extended-status或show global status直接得到，但是十分重要。
response time: 响应时间
Percona提供了tcprstat工具统计响应时间，此功能默认是关闭的，可以通过设置参数query_response_time_stats=1打开这个功能。
有两种方法查看响应时间：
（1）通过命令SHOW QUERY_RESPONSE_TIME查看响应时间统计；
（2）通过INFORMATION_SCHEMA里面的表QUERY_RESPONSE_TIME来查看。
Slave delay: 备库延迟
可以在slave节点上执行show slave status\G命令，Seconds_Behind_Master项的值即为slave当前的延时量，单位秒。
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