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| |
| # EXPLAIN |
| |
| The `EXPLAIN` command shows the logical and physical execution plan for the specified SQL statement. |
| |
| <pre> |
| EXPLAIN [ANALYZE] [VERBOSE] statement |
| </pre> |
| |
| ## EXPLAIN |
| |
| Shows the execution plan of a statement. |
| If you need more details output, try to use `EXPLAIN VERBOSE`. |
| |
| ```sql |
| EXPLAIN SELECT SUM(x) FROM table GROUP BY b; |
| +---------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------+ |
| | plan_type | plan | |
| +---------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------+ |
| | logical_plan | Projection: #SUM(table.x) | |
| | | Aggregate: groupBy=[[#table.b]], aggr=[[SUM(#table.x)]] | |
| | | TableScan: table projection=[x, b] | |
| | physical_plan | ProjectionExec: expr=[SUM(table.x)@1 as SUM(table.x)] | |
| | | AggregateExec: mode=FinalPartitioned, gby=[b@0 as b], aggr=[SUM(table.x)] | |
| | | CoalesceBatchesExec: target_batch_size=4096 | |
| | | RepartitionExec: partitioning=Hash([Column { name: "b", index: 0 }], 16) | |
| | | AggregateExec: mode=Partial, gby=[b@1 as b], aggr=[SUM(table.x)] | |
| | | RepartitionExec: partitioning=RoundRobinBatch(16) | |
| | | CsvExec: source=Path(/tmp/table.csv: [/tmp/table.csv]), has_header=false, limit=None, projection=[x, b] | |
| | | | |
| +---------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------+ |
| ``` |
| |
| ## EXPLAIN ANALYZE |
| |
| Shows the execution plan and metrics of a statement. |
| If you need more information output, try to use `EXPLAIN ANALYZE VERBOSE`. |
| |
| ```sql |
| EXPLAIN ANALYZE SELECT SUM(x) FROM table GROUP BY b; |
| +-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------+ |
| | plan_type | plan | |
| +-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------+ |
| | Plan with Metrics | CoalescePartitionsExec, metrics=[] | |
| | | ProjectionExec: expr=[SUM(table.x)@1 as SUM(x)], metrics=[] | |
| | | HashAggregateExec: mode=FinalPartitioned, gby=[b@0 as b], aggr=[SUM(x)], metrics=[outputRows=2] | |
| | | CoalesceBatchesExec: target_batch_size=4096, metrics=[] | |
| | | RepartitionExec: partitioning=Hash([Column { name: "b", index: 0 }], 16), metrics=[sendTime=839560, fetchTime=122528525, repartitionTime=5327877] | |
| | | HashAggregateExec: mode=Partial, gby=[b@1 as b], aggr=[SUM(x)], metrics=[outputRows=2] | |
| | | RepartitionExec: partitioning=RoundRobinBatch(16), metrics=[fetchTime=5660489, repartitionTime=0, sendTime=8012] | |
| | | CsvExec: source=Path(/tmp/table.csv: [/tmp/table.csv]), has_header=false, metrics=[] | |
| +-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------+ |
| ``` |
