本文介紹了TRACE語句的用法。
TRACE語句用於查看具體SQL的執行情況。TRACE [SQL]和SHOW TRACE要結合使用。
說明 TRACE SQL和EXPLAIN SQL的區別在於TRACE SQL會實際執行該語句。
樣本
查看select 1這條語句的執行情況。
mysql> trace select 1;
+---+
| 1 |
+---+
| 1 |
+---+
1 row in set (0.03 sec)
mysql> show trace;
+------+----------+----------------+-----------------------------------+---------------+--------------------------+------+-----------+--------+
| ID | TYPE | GROUP_NAME | DBKEY_NAME | TIME_COST(MS) | CONNECTION_TIME_COST(MS) | ROWS | STATEMENT | PARAMS |
+------+----------+----------------+-----------------------------------+---------------+--------------------------+------+-----------+--------+
| 0 | Optimize | DRDS | DRDS | 3 | 0.00 | 0 | select 1 | NULL |
| 1 | Query | TDDL5_00_GROUP | db218249098_sqa_zmf_tddl5_00_3309 | 7 | 0.15 | 1 | select 1 | NULL |
+------+----------+----------------+-----------------------------------+---------------+--------------------------+------+-----------+--------+
2 rows in set (0.01 sec)