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

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)
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

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