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EXPLAIN FRAGMENTS

Shows the distributed execution plan of a SQL statement.

This command transforms the execution plan of a SQL statement into plan fragments where you can see the process of retrieving the data you need from Databend.

Syntax​

EXPLAIN FRAGMENTS <statement>

Examples​

EXPLAIN FRAGMENTS select COUNT() from numbers(10) GROUP BY number % 3;

+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| explain                                                                                                                                                                     |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Fragment 0:                                                                                                                                                                 |
|   DataExchange: Shuffle                                                                                                                                                     |
|   AggregatorPartial: groupBy=[[(number % 3)]], aggr=[[COUNT()]]                                                                                                             |
|     Expression: (number % 3):UInt8 (Before GroupBy)                                                                                                                         |
|       ReadDataSource: scan schema: [number:UInt64], statistics: [read_rows: 10, read_bytes: 80, partitions_scanned: 1, partitions_total: 1], push_downs: [projections: [0]] |
|                                                                                                                                                                             |
| Fragment 2:                                                                                                                                                                 |
|   DataExchange: Merge                                                                                                                                                       |
|   Projection: COUNT():UInt64                                                                                                                                                |
|     AggregatorFinal: groupBy=[[(number % 3)]], aggr=[[COUNT()]]                                                                                                             |
|       Remote[receive fragment: 0]                                                                                                                                           |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
11 rows in set (0.02 sec)