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ebnf trace (#16996) #17115

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Apr 10, 2024
Merged

ebnf trace (#16996) #17115

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31d84b6
ebnf trace
dveeden Apr 8, 2024
5d08d9d
Update content order in a table
lilin90 Apr 10, 2024
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52 changes: 43 additions & 9 deletions sql-statements/sql-statement-trace.md
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Expand Up @@ -9,20 +9,26 @@ The `TRACE` statement provides detailed information about query execution. It is

## Synopsis

**TraceStmt:**
```ebnf+diagram
TraceStmt ::=
"TRACE" ( "FORMAT" "=" stringLit )? TracableStmt

![TraceStmt](/media/sqlgram/TraceStmt.png)

**TraceableStmt:**
TracableStmt ::=
( SelectStmt | DeleteFromStmt | UpdateStmt | InsertIntoStmt | ReplaceIntoStmt | UnionStmt | LoadDataStmt | BeginTransactionStmt | CommitStmt | RollbackStmt | SetStmt )
```

![TraceableStmt](/media/sqlgram/TraceableStmt.png)
| Format | Description |
|--------|------------------------------------|
| row | Output in a tree format |
| json | Structured output in JSON format |
| log | Log based output |

## Examples

{{< copyable "sql" >}}
### Row

```sql
trace format='row' select * from mysql.user;
TRACE FORMAT='row' SELECT * FROM mysql.user;
```

```
Expand All @@ -46,10 +52,10 @@ trace format='row' select * from mysql.user;
13 rows in set (0.00 sec)
```

{{< copyable "sql" >}}
### JSON

```sql
trace format='json' select * from mysql.user;
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:
Expand All @@ -58,6 +64,34 @@ The JSON formatted trace can be pasted into the trace viewer, which is accessed

![TiDB Trace Viewer-2](/media/trace-view.png)

### Log

```sql
TRACE FORMAT='log' SELECT * FROM mysql.user;
```

```
+----------------------------+--------------------------------------------------------+------+------------------------------------+
| time | event | tags | spanName |
+----------------------------+--------------------------------------------------------+------+------------------------------------+
| 2024-04-08 08:41:47.358734 | --- start span trace ---- | | trace |
| 2024-04-08 08:41:47.358737 | --- start span session.ExecuteStmt ---- | | session.ExecuteStmt |
| 2024-04-08 08:41:47.358746 | --- start span executor.Compile ---- | | executor.Compile |
| 2024-04-08 08:41:47.358984 | --- start span session.runStmt ---- | | session.runStmt |
| 2024-04-08 08:41:47.359035 | --- start span TableReaderExecutor.Open ---- | | TableReaderExecutor.Open |
| 2024-04-08 08:41:47.359047 | --- start span distsql.Select ---- | | distsql.Select |
| 2024-04-08 08:41:47.359073 | --- start span *executor.TableReaderExecutor.Next ---- | | *executor.TableReaderExecutor.Next |
| 2024-04-08 08:41:47.359077 | table scan table: user, range: [[-inf,+inf]] | | *executor.TableReaderExecutor.Next |
| 2024-04-08 08:41:47.359094 | --- start span regionRequest.SendReqCtx ---- | | regionRequest.SendReqCtx |
| 2024-04-08 08:41:47.359098 | send Cop request to region 16 at store1 | | regionRequest.SendReqCtx |
| 2024-04-08 08:41:47.359237 | --- start span *executor.TableReaderExecutor.Next ---- | | *executor.TableReaderExecutor.Next |
| 2024-04-08 08:41:47.359240 | table scan table: user, range: [[-inf,+inf]] | | *executor.TableReaderExecutor.Next |
| 2024-04-08 08:41:47.359242 | execute done, ReturnRow: 1, ModifyRow: 0 | | trace |
| 2024-04-08 08:41:47.359252 | execute done, modify row: 0 | | trace |
+----------------------------+--------------------------------------------------------+------+------------------------------------+
14 rows in set (0.0008 sec)
```

## MySQL compatibility

This statement is a TiDB extension to MySQL syntax.
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