TRACE

TRACE 语句用于提供查询执行的详细信息，可通过 TiDB 服务器状态端口所公开的图形界面进行查看。

语法图

TraceStmt:

TraceableStmt:

示例

mysql> trace format='row' select * from mysql.user;
+---------------------------+-----------------+------------+
| operation                 | startTS         | duration   |
+---------------------------+-----------------+------------+
| session.getTxnFuture      | 10:33:34.647148 | 3.847µs    |
|   ├─session.Execute       | 10:33:34.647146 | 536.233µs  |
|   ├─session.ParseSQL      | 10:33:34.647182 | 19.868µs   |
|   ├─executor.Compile      | 10:33:34.647219 | 295.688µs  |
|   ├─session.runStmt       | 10:33:34.647533 | 116.229µs  |
|   ├─session.CommitTxn     | 10:33:34.647631 | 5.44µs     |
|   ├─recordSet.Next        | 10:33:34.647707 | 833.103µs  |
|   ├─tableReader.Next      | 10:33:34.647709 | 806.783µs  |
|   ├─recordSet.Next        | 10:33:34.648572 | 19.367µs   |
|   └─tableReader.Next      | 10:33:34.648575 | 1.783µs    |
+---------------------------+-----------------+------------+
 rows in set (0.00 sec)
mysql> CREATE TABLE t1 (id int not null primary key auto_increment);
Query OK, 0 rows affected (0.11 sec)
mysql> INSERT INTO t1 VALUES (1),(2),(3),(4),(5);
Query OK, 5 rows affected (0.02 sec)
Records: 5  Duplicates: 0  Warnings: 0
mysql> TRACE FORMAT='json' SELECT * FROM t1 WHERE id = 2\G
operation: [
    {"ID":{"Trace":"60d20d005593de87","Span":"44e5b309242ffe2f","Parent":"79d146dac9a29a7e"},
        "Annotations":[
            {"Key":"Name","Value":"c2Vzc2lvbi5nZXRUeG5GdXR1cmU="},
            {"Key":"_schema:name","Value":null},
            {"Key":"Span.Start","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE2MTQ3ODYtMDY6MDA="},
            {"Key":"Span.End","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE2MjA0MDYtMDY6MDA="},
            {"Key":"_schema:Timespan","Value":null}
        ],
        "Sub":[
            {"ID":{"Trace":"60d20d005593de87","Span":"4dbf8f2ca373b4b0","Parent":"79d146dac9a29a7e"},
            "Annotations":[
                {"Key":"Name","Value":"c2Vzc2lvbi5QYXJzZVNRTA=="},
                {"Key":"_schema:name","Value":null},
                {"Key":"Span.Start","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE2NjE1MTQtMDY6MDA="},
                {"Key":"Span.End","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE3MDYxNjgtMDY6MDA="},
                {"Key":"_schema:Timespan","Value":null}
            ],
            "Sub":null},
            {"ID":{"Trace":"60d20d005593de87","Span":"6b6d6916df809604","Parent":"79d146dac9a29a7e"},
            "Annotations":[
                {"Key":"Name","Value":"ZXhlY3V0b3IuQ29tcGlsZQ=="},
                {"Key":"_schema:name","Value":null},
                {"Key":"Span.End","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE3NTcyODUtMDY6MDA="},
                {"Key":"Span.Start","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE3MzE0MjYtMDY6MDA="},
                {"Key":"_schema:Timespan","Value":null}
            ],
            "Sub":null},
            {"ID":{"Trace":"60d20d005593de87","Span":"3f1bcdd402a72911","Parent":"79d146dac9a29a7e"},
            "Annotations":[
                {"Key":"Name","Value":"c2Vzc2lvbi5Db21taXRUeG4="},
                {"Key":"_schema:name","Value":null},
                {"Key":"Span.Start","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE3OTgyNjItMDY6MDA="},
                {"Key":"Span.End","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE4MDU1NzYtMDY6MDA="},
                {"Key":"_schema:Timespan","Value":null}
            ],
            "Sub":null},
            {"ID":{"Trace":"60d20d005593de87","Span":"58c1f7d66dc5afbc","Parent":"79d146dac9a29a7e"},
            "Annotations":[
                {"Key":"Name","Value":"c2Vzc2lvbi5ydW5TdG10"},
                {"Key":"_schema:name","Value":null},
                {"Key":"Msg","Value":"eyJzcWwiOiJTRUxFQ1QgKiBGUk9NIHQxIFdIRVJFIGlkID0gMiJ9"},
                {"Key":"Time","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE3ODA1NjgtMDY6MDA="},
                {"Key":"_schema:log","Value":null},
                {"Key":"Span.End","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE4MTk5MzMtMDY6MDA="},
                {"Key":"Span.Start","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE3NzcyNDItMDY6MDA="},
                {"Key":"_schema:Timespan","Value":null}
            ],
            "Sub":null},
            {"ID":{"Trace":"60d20d005593de87","Span":"6bd8cc440fb31ed7","Parent":"79d146dac9a29a7e"},
            "Annotations":[
                {"Key":"Name","Value":"c2Vzc2lvbi5FeGVjdXRl"},
                {"Key":"_schema:name","Value":null},
                {"Key":"Span.Start","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE2MTEwODktMDY6MDA="},
                {"Key":"Span.End","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE4NTU0My0wNjowMA=="},
                {"Key":"_schema:Timespan","Value":null}
            ],
            "Sub":null},
            {"ID":{"Trace":"60d20d005593de87","Span":"61d0b809f6cc018b","Parent":"79d146dac9a29a7e"},
            "Annotations":[
                {"Key":"Name","Value":"cmVjb3JkU2V0Lk5leHQ="},
                {"Key":"_schema:name","Value":null},
                {"Key":"Span.Start","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDE4NzQ1NTYtMDY6MDA="},
                {"Key":"Span.End","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDIyOTg4NjYtMDY6MDA="},
                {"Key":"_schema:Timespan","Value":null}
            ],
            "Sub":null},
            {"ID":{"Trace":"60d20d005593de87","Span":"2bd2c3d47ccb1133","Parent":"79d146dac9a29a7e"},
            "Annotations":[
                {"Key":"Name","Value":"cmVjb3JkU2V0Lk5leHQ="},
                {"Key":"_schema:name","Value":null},
                {"Key":"Span.Start","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDIzMjY0ODgtMDY6MDA="},
                {"Key":"Span.End","Value":"MjAxOS0wNC0xN1QxMDozOToxMC45NDIzMjkwMDMtMDY6MDA="},
                {"Key":"_schema:Timespan","Value":null}
            ],
            "Sub":null}
        ]
    }
]
 row in set (0.00 sec)

可将 JSON 格式的跟踪文件粘贴到跟踪查看器中。查看器可通过 TiDB 状态端口访问：

MySQL 兼容性

TRACE 语句是 TiDB 对 MySQL 语法的扩展。

另请参阅

• EXPLAIN ANALYZE