mysql常用

性能分析

-- 查看sql执行次数
SELECT
    DIGEST_TEXT,
    COUNT_STAR AS EXECUTION_COUNT
FROM
    performance_schema.events_statements_summary_by_digest
WHERE
        COUNT_STAR > 0
ORDER BY
    EXECUTION_COUNT DESC;

-- 查看占用时间
SELECT
    DIGEST_TEXT,
    MAX_TIMER_WAIT / 1000000 AS MAX_EXECUTION_TIME_MS
FROM
    performance_schema.events_statements_summary_by_digest
WHERE
    MAX_TIMER_WAIT IS NOT NULL
ORDER BY
    MAX_EXECUTION_TIME_MS DESC;

-- 查看表空间大小
    SELECT
        table_schema AS `Database`,
        table_name AS `Table`,
        ROUND(((data_length + index_length) / 1024 / 1024), 2) AS `Size (MB)`
    FROM
        information_schema.tables
    WHERE
        table_schema = 'table_name';

-- 查询数据库占用空间    
SELECT table_name AS `Table`, 
       ROUND((data_length + index_length) / 1024 / 1024, 2) AS `Size (MB)`
FROM information_schema.tables
WHERE table_schema = 'your_database_name'
ORDER BY (data_length + index_length) DESC;