EXPLAIN command
The EXPLAIN command returns the logical plan and the physical plan for the
specified SQL statement.
EXPLAIN [ANALYZE] [VERBOSE] statement
EXPLAIN
Returns the logical plan and physical (execution) plan of a statement.
To output more details, use EXPLAIN VERBOSE.
EXPLAIN doesn’t execute the statement.
To execute the statement and view runtime metrics, use EXPLAIN ANALYZE.
Example EXPLAIN
EXPLAIN
SELECT
room,
avg(temp) AS temp
FROM home
GROUP BY room
View EXPLAIN example output
| plan_type | plan | |
|---|---|---|
| 0 | logical_plan | Projection: home.room, AVG(home.temp) AS temp |
| Aggregate: groupBy=[[home.room]], aggr=[[AVG(home.temp)]] | ||
| TableScan: home projection=[room, temp] | ||
| 1 | physical_plan | ProjectionExec: expr=[room@0 as room, AVG(home.temp)@1 as temp] |
| AggregateExec: mode=FinalPartitioned, gby=[room@0 as room], aggr=[AVG(home.temp)] | ||
| CoalesceBatchesExec: target_batch_size=8192 | ||
| RepartitionExec: partitioning=Hash([room@0], 8), input_partitions=8 | ||
| AggregateExec: mode=Partial, gby=[room@0 as room], aggr=[AVG(home.temp)] | ||
| ParquetExec: file_groups={8 groups: [[70434/116281/404d73cea0236530ea94f5470701eb814a8f0565c0e4bef5a2d2e33dfbfc3567/1be334e8-0af8-00da-2615-f67cd4be90f7.parquet, 70434/116281/b7a9e7c57fbfc3bba9427e4b3e35c89e001e2e618b0c7eb9feb4d50a3932f4db/d29370d4-262f-0d32-2459-fe7b099f682f.parquet], [70434/116281/c14418ba28a22a3abb693a1cb326a63b62dc611aec58c9bed438fdafd3bc5882/8b29ae98-761f-0550-2fe4-ee77503658e9.parquet], [70434/116281/fa677477eed622ae8123da1251aa7c351f801e2ee2f0bc28c0fe3002a30b3563/65bb4dc3-04e1-0e02-107a-90cee83c51b0.parquet], [70434/116281/db162bdd30261019960dd70da182e6ebd270284569ecfb5deffea7e65baa0df9/2505e079-67c5-06d9-3ede-89aca542dd18.parquet], [70434/116281/0c025dcccae8691f5fd70b0f131eea4ca6fafb95a02f90a3dc7bb015efd3ab4f/3f3e44c3-b71e-0ca4-3dc7-8b2f75b9ff86.parquet], …]}, projection=[room, temp] |
EXPLAIN ANALYZE
Executes a statement and returns the execution plan and runtime metrics of the statement. The report includes the logical plan and the physical plan annotated with execution counters, number of rows produced, and runtime metrics sampled during the query execution.
If the plan requires reading lots of data files, EXPLAIN and EXPLAIN ANALYZE may truncate the list of files in the report.
To output more information, including intermediate plans and paths for all scanned Parquet files, use EXPLAIN ANALYZE VERBOSE.
Example EXPLAIN ANALYZE
EXPLAIN ANALYZE
SELECT
room,
avg(temp) AS temp
FROM home
WHERE time >= '2023-01-01' AND time <= '2023-12-31'
GROUP BY room
View EXPLAIN ANALYZE example output
| plan_type | plan | |
|---|---|---|
| 0 | Plan with Metrics | ProjectionExec: expr=[room@0 as room, AVG(home.temp)@1 as temp], metrics=[output_rows=2, elapsed_compute=4.768µs] |
| AggregateExec: mode=FinalPartitioned, gby=[room@0 as room], aggr=[AVG(home.temp)], ordering_mode=Sorted, metrics=[output_rows=2, elapsed_compute=140.405µs] | ||
| CoalesceBatchesExec: target_batch_size=8192, metrics=[output_rows=2, elapsed_compute=6.821µs] | ||
| RepartitionExec: partitioning=Hash([room@0], 8), input_partitions=8, preserve_order=true, sort_exprs=room@0 ASC, metrics=[output_rows=2, elapsed_compute=18.408µs, repart_time=59.698µs, fetch_time=1.057882762s, send_time=5.83µs] | ||
| AggregateExec: mode=Partial, gby=[room@0 as room], aggr=[AVG(home.temp)], ordering_mode=Sorted, metrics=[output_rows=2, elapsed_compute=137.577µs] | ||
| RepartitionExec: partitioning=RoundRobinBatch(8), input_partitions=6, preserve_order=true, sort_exprs=room@0 ASC, metrics=[output_rows=46, elapsed_compute=26.637µs, repart_time=6ns, fetch_time=399.971411ms, send_time=6.658µs] | ||
| ProjectionExec: expr=[room@0 as room, temp@2 as temp], metrics=[output_rows=46, elapsed_compute=3.102µs] | ||
| CoalesceBatchesExec: target_batch_size=8192, metrics=[output_rows=46, elapsed_compute=25.585µs] | ||
| FilterExec: time@1 >= 1672531200000000000 AND time@1 <= 1703980800000000000, metrics=[output_rows=46, elapsed_compute=26.51µs] | ||
| ParquetExec: file_groups={6 groups: [[70434/116281/404d73cea0236530ea94f5470701eb814a8f0565c0e4bef5a2d2e33dfbfc3567/1be334e8-0af8-00da-2615-f67cd4be90f7.parquet], [70434/116281/c14418ba28a22a3abb693a1cb326a63b62dc611aec58c9bed438fdafd3bc5882/8b29ae98-761f-0550-2fe4-ee77503658e9.parquet], [70434/116281/fa677477eed622ae8123da1251aa7c351f801e2ee2f0bc28c0fe3002a30b3563/65bb4dc3-04e1-0e02-107a-90cee83c51b0.parquet], [70434/116281/db162bdd30261019960dd70da182e6ebd270284569ecfb5deffea7e65baa0df9/2505e079-67c5-06d9-3ede-89aca542dd18.parquet], [70434/116281/0c025dcccae8691f5fd70b0f131eea4ca6fafb95a02f90a3dc7bb015efd3ab4f/3f3e44c3-b71e-0ca4-3dc7-8b2f75b9ff86.parquet], …]}, projection=[room, time, temp], output_ordering=[room@0 ASC, time@1 ASC], predicate=time@6 >= 1672531200000000000 AND time@6 <= 1703980800000000000, pruning_predicate=time_max@0 >= 1672531200000000000 AND time_min@1 <= 1703980800000000000, required_guarantees=[], metrics=[output_rows=46, elapsed_compute=6ns, predicate_evaluation_errors=0, bytes_scanned=3279, row_groups_pruned_statistics=0, file_open_errors=0, file_scan_errors=0, pushdown_rows_filtered=0, num_predicate_creation_errors=0, row_groups_pruned_bloom_filter=0, page_index_rows_filtered=0, time_elapsed_opening=398.462968ms, time_elapsed_processing=1.626106ms, time_elapsed_scanning_total=1.36822ms, page_index_eval_time=33.474µs, pushdown_eval_time=14.267µs, time_elapsed_scanning_until_data=1.27694ms] |
EXPLAIN ANALYZE VERBOSE
Executes a statement and returns the execution plan, runtime metrics, and additional details helpful for debugging the statement.
The report includes the following:
- the logical plan
- the physical plan annotated with execution counters, number of rows produced, and runtime metrics sampled during the query execution
- Information truncated in the
EXPLAINreport–for example, the paths for all Parquet files retrieved for the query. - All intermediate physical plans that DataFusion and the Querier generate before generating the final physical plan–helpful in debugging to see when an
ExecutionPlannode is added or removed, and how InfluxDB optimizes the query.
Example EXPLAIN ANALYZE VERBOSE
EXPLAIN ANALYZE VERBOSE SELECT temp FROM home
WHERE time >= now() - INTERVAL '7 days' AND room = 'Kitchen'
ORDER BY time
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