51工具盒子MySQL的InnoDB缓存命中率是指查询时从数据库缓存中获取数据的比率。在MySQL中，有一个称为查询缓存的特性，它可以将查询的结果缓存起来，当相同的查询再次执行时，如果数据在缓存中已经存在，就不需要再次访问数据库表，而是直接从缓存中获取数据，从而提高查询性能。
MySQL的InnoDB缓存命中率对于数据库性能非常重要。高的缓存命中率意味着大部分的查询都能够从缓存中获取数据，从而减少了对数据库表的访问，加快了查询速度。这对于频繁查询相同数据的场景非常有益，例如网站上的热门文章、评论等。通过缓存命中率的提高，可以显著减轻数据库的负载，提高整体系统性能。
通过优化InnoDB缓存命中率，可以提高查询性能和整体系统的响应速度。但需要注意平衡内存资源和性能要求，避免过度缓存导致内存压力过大。
吴昊这里提供两种MySQL的InnoDB缓存命中率查询脚本，一个是使用MySQL账号密码查询，另一个通过默认的匿名用户直接查询。
脚本一：
通过设置MySQL的只读账号密码，来读取数据，计算MySQL的缓存命中率。
#!/bin/bash # MySQL信息 MYSQL_USER="read_only" MYSQL_PASS="12345678" MYSQL_BIN="/usr/local/mysql/bin/mysql" # 获取缓存命中率 get_cache_hit_ratio() { # 获取InnoDB缓冲池的读取请求数 query="SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_read_requests';" read_requests=$("$MYSQL_BIN" -u"$MYSQL_USER" -p"$MYSQL_PASS" -h"127.0.0.1" -e "$query" 2>/dev/null | grep -oP '\d+') # 获取InnoDB缓冲池的实际读取次数 query="SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_reads';" read_hits=$("$MYSQL_BIN" -u"$MYSQL_USER" -p"$MYSQL_PASS" -h"127.0.0.1" -e "$query" 2>/dev/null | grep -oP '\d+') # 检查是否成功获取缓存统计信息 if [[ -z "$read_requests" || -z "$read_hits" ]]; then echo "Error: Unable to fetch cache statistics from MySQL." exit 1 fi # 计算缓存命中率 cache_hit_ratio=$(bc <<< "scale=2; 100 * ($read_requests - $read_hits) / $read_requests") echo "InnoDB缓存命中率: $cache_hit_ratio%" } get_cache_hit_ratio
|-------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | #!/bin/bash # MySQL信息 MYSQL_USER="read_only" MYSQL_PASS="12345678" MYSQL_BIN="/usr/local/mysql/bin/mysql" # 获取缓存命中率 get_cache_hit_ratio() { # 获取InnoDB缓冲池的读取请求数 query="SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_read_requests';" read_requests=$("$MYSQL_BIN" -u"$MYSQL_USER" -p"$MYSQL_PASS" -h"127.0.0.1" -e "$query" 2>/dev/null | grep -oP '\d+') # 获取InnoDB缓冲池的实际读取次数 query="SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_reads';" read_hits=$("$MYSQL_BIN" -u"$MYSQL_USER" -p"$MYSQL_PASS" -h"127.0.0.1" -e "$query" 2>/dev/null | grep -oP '\d+') # 检查是否成功获取缓存统计信息 if [[ -z "$read_requests" || -z "$read_hits" ]]; then echo "Error: Unable to fetch cache statistics from MySQL." exit 1 fi # 计算缓存命中率 cache_hit_ratio=$(bc <<< "scale=2; 100 * ($read_requests - $read_hits) / $read_requests") echo "InnoDB缓存命中率: $cache_hit_ratio%" } get_cache_hit_ratio |
脚本二：
通过MySQL的匿名方式，直接使用-e参数读取数据，计算MySQL的缓存命中率。
#!/bin/bash # MySQL信息 MYSQL_BIN="/usr/local/mysql/bin/mysql" # 获取缓存命中率 get_cache_hit_ratio() { # 获取InnoDB缓冲池的读取请求数 query="SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_read_requests';" read_requests=$("$MYSQL_BIN" -e "$query" 2>/dev/null | grep -oP '\d+') # 获取InnoDB缓冲池的实际读取次数 query="SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_reads';" read_hits=$("$MYSQL_BIN" -e "$query" 2>/dev/null | grep -oP '\d+') # 检查是否成功获取缓存统计信息 if [[ -z "$read_requests" || -z "$read_hits" ]]; then echo "Error: Unable to fetch cache statistics from MySQL." exit 1 fi # 计算缓存命中率 cache_hit_ratio=$(bc <<< "scale=2; 100 * ($read_requests - $read_hits) / $read_requests") echo "InnoDB缓存命中率: $cache_hit_ratio%" } get_cache_hit_ratio
|-------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | #!/bin/bash # MySQL信息 MYSQL_BIN="/usr/local/mysql/bin/mysql" # 获取缓存命中率 get_cache_hit_ratio() { # 获取InnoDB缓冲池的读取请求数 query="SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_read_requests';" read_requests=$("$MYSQL_BIN" -e "$query" 2>/dev/null | grep -oP '\d+') # 获取InnoDB缓冲池的实际读取次数 query="SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_reads';" read_hits=$("$MYSQL_BIN" -e "$query" 2>/dev/null | grep -oP '\d+') # 检查是否成功获取缓存统计信息 if [[ -z "$read_requests" || -z "$read_hits" ]]; then echo "Error: Unable to fetch cache statistics from MySQL." exit 1 fi # 计算缓存命中率 cache_hit_ratio=$(bc <<< "scale=2; 100 * ($read_requests - $read_hits) / $read_requests") echo "InnoDB缓存命中率: $cache_hit_ratio%" } get_cache_hit_ratio |
