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:

TraceStmt

TraceableStmt:

TraceableStmt

示例

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;

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:

TiDB Trace Viewer-1

TiDB Trace Viewer-2

MySQL 兼容性

TRACE 语句是 TiDB 对 MySQL 语法的扩展。

另请参阅

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