獲取表鎖資訊

SELECT  
    r.trx_id waiting_trx_id,  
    r.trx_mysql_thread_id waiting_thread,  
    TIMESTAMPDIFF(  
        SECOND,  
        r.trx_wait_started,  
        CURRENT_TIMESTAMP  
    ) wait_time,  
    r.trx_query waiting_query,  
    l.lock_table waiting_table_lock,  
    b.trx_id blocking_trx_id,  
    b.trx_mysql_thread_id blocking_thread,  
    SUBSTRING(  
        p. HOST,  
        1,  
        INSTR(p. HOST, ':') - 1  
    ) blocking_host,  
    SUBSTRING(p. HOST, INSTR(p. HOST, ':') + 1) blocking_port,  
  
IF (p.COMMAND = 'Sleep', p.TIME, 0) idel_in_trx,  
 b.trx_query blocking_query  
FROM  
    information_schema.INNODB_LOCK_WAITS w  
INNER JOIN information_schema.INNODB_TRX b ON b.trx_id = w.blocking_trx_id  
INNER JOIN information_schema.INNODB_TRX r ON r.trx_id = w.requesting_trx_id  
INNER JOIN information_schema.INNODB_LOCKS l ON w.requested_lock_id = l.lock_id  
LEFT JOIN information_schema. PROCESSLIST p ON p.ID = b.trx_mysql_thread_id  
ORDER BY  
    wait_time DESC;
 

記得以前，當出現：ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction，要解決是一件麻煩的事情；特別是當一個SQL執行完了，但未COMMIT，後面的SQL想要執行就是被鎖，超時結束，DBA光從資料庫無法著手找出源頭是哪個SQL鎖住了；有時候看看 show engine innodb status， 並結合 show full processlist 能暫時解決問題，但一直不能精確定位。