| 指標 | 計算公式 | 獲取指令 | 健康閾值參考 |
|---|
| QPS (每秒查詢數) | Questions / Uptime | SHOW GLOBAL STATUS LIKE 'Questions'; | 視業務而定，突增需警戒 |
| TPS (每秒事務數) | (Com_commit + Com_rollback) / Uptime | SHOW GLOBAL STATUS LIKE 'Com_commit'; SHOW ... LIKE 'Com_rollback'; | 同上 |
| Key Buffer 讀命中率 | (1 - Key_reads / Key_read_requests) * 100% | SHOW GLOBAL STATUS LIKE 'Key_read%'; | > 99% |
| Key Buffer 寫命中率 | (1 - Key_writes / Key_write_requests) * 100% | SHOW GLOBAL STATUS LIKE 'Key_write%'; | > 95% |
| InnoDB Buffer 讀命中率 | (1 - Innodb_buffer_pool_reads / Innodb_buffer_pool_read_requests) * 100% | SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_read%'; | > 99% |
| Query Cache 命中率 | Qcache_hits / (Qcache_hits + Qcache_inserts) * 100% | SHOW GLOBAL STATUS LIKE 'Qcache%'; | > 80% (若啟用 QC) |
| Table Cache 狀態 | Open_tables / Opened_tables | SHOW GLOBAL STATUS LIKE 'Open%tables'; | Open_tables 接近 table_open_cache 需調大 |
| Thread Cache 命中率 | (1 - Threads_created / Connections) * 100% | SHOW GLOBAL STATUS LIKE 'Thread%'; SHOW ... LIKE 'Connections'; | > 90% |
| 鎖狀態 | Table_locks_waited / Table_locks_immediate | SHOW GLOBAL STATUS LIKE '%lock%'; | waited / immediate < 1% |
| 複寫延遲 | Seconds_Behind_Master | SHOW SLAVE STATUS\G | = 0 (理想)，< 10 秒可接受 |
| 臨時表磁碟化 | Created_tmp_disk_tables / Created_tmp_tables * 100% | SHOW GLOBAL STATUS LIKE 'Created_tmp%'; | < 25% |
| Binlog Cache 使用 | Binlog_cache_disk_use / Binlog_cache_use | SHOW GLOBAL STATUS LIKE 'Binlog_cache%'; | disk_use = 0 最佳 |
| InnoDB Log Waits | Innodb_log_waits | SHOW GLOBAL STATUS LIKE 'innodb_log_waits'; | = 0 |
