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sql-statement-trace.md

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TRACE | TiDB SQL Statement Reference
An overview of the usage of TRACE for the TiDB database.

TRACE

The TRACE statement provides detailed information about query execution. It is intended to be viewed through a Graphical interface exposed by the TiDB server's status port.

Synopsis

TraceStmt:

TraceStmt

TraceableStmt:

TraceableStmt

Examples

{{< copyable "sql" >}}

trace format='row' select * from mysql.user;
+--------------------------------------------+-----------------+------------+
| operation                                  | startTS         | duration   |
+--------------------------------------------+-----------------+------------+
| trace                                      | 17:03:31.938237 | 886.086µs  |
|   ├─session.Execute                        | 17:03:31.938247 | 507.812µs  |
|   │ ├─session.ParseSQL                     | 17:03:31.938254 | 22.504µs   |
|   │ ├─executor.Compile                     | 17:03:31.938321 | 278.931µs  |
|   │ │ └─session.getTxnFuture               | 17:03:31.938337 | 1.515µs    |
|   │ └─session.runStmt                      | 17:03:31.938613 | 109.578µs  |
|   │   ├─TableReaderExecutor.Open           | 17:03:31.938645 | 50.657µs   |
|   │   │ └─distsql.Select                   | 17:03:31.938666 | 21.066µs   |
|   │   │   └─RPCClient.SendRequest          | 17:03:31.938799 | 158.411µs  |
|   │   └─session.CommitTxn                  | 17:03:31.938705 | 12.06µs    |
|   │     └─session.doCommitWitRetry         | 17:03:31.938709 | 2.437µs    |
|   ├─*executor.TableReaderExecutor.Next     | 17:03:31.938781 | 224.327µs  |
|   └─*executor.TableReaderExecutor.Next     | 17:03:31.939019 | 6.266µs    |
+--------------------------------------------+-----------------+------------+
13 rows in set (0.00 sec)

{{< copyable "sql" >}}

trace format='json' select * from mysql.user;

The JSON formatted trace can be pasted into the trace viewer, which is accessed via the TiDB status port:

TiDB Trace Viewer-1

TiDB Trace Viewer-2

MySQL compatibility

This statement is a TiDB extension to MySQL syntax.

See also