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Explain

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The EXPLAIN command returns the logical plan and the physical plan for the specified SQL statement.

sql
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

sql
EXPLAIN
SELECT
  room,
  avg(temp) AS temp
FROM home
GROUP BY room

{{< expand-wrapper >}} {{% expand "View EXPLAIN example output" %}}

plan_typeplan
0logical_plan<span style="white-space:pre-wrap;"> Projection: home.room, AVG(home.temp) AS temp </span>
<span style="white-space:pre-wrap;"> Aggregate: groupBy=[[home.room]], aggr=[[AVG(home.temp)]] </span>
<span style="white-space:pre-wrap;"> TableScan: home projection=[room, temp] </span>
1physical_plan<span style="white-space:pre-wrap;"> ProjectionExec: expr=[room@0 as room, AVG(home.temp)@1 as temp] </span>
<span style="white-space:pre-wrap;"> AggregateExec: mode=FinalPartitioned, gby=[room@0 as room], aggr=[AVG(home.temp)] </span>
<span style="white-space:pre-wrap;"> CoalesceBatchesExec: target_batch_size=8192 </span>
<span style="white-space:pre-wrap;"> RepartitionExec: partitioning=Hash([room@0], 8), input_partitions=8 </span>
<span style="white-space:pre-wrap;"> AggregateExec: mode=Partial, gby=[room@0 as room], aggr=[AVG(home.temp)] </span>
<span style="white-space:pre-wrap;"> 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] </span>

{{% /expand %}} {{< /expand-wrapper >}}

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

sql
EXPLAIN ANALYZE
SELECT
  room,
  avg(temp) AS temp
FROM home
WHERE time >= '2023-01-01' AND time <= '2023-12-31'
GROUP BY room

{{< expand-wrapper >}} {{% expand "View EXPLAIN ANALYZE example output" %}}

plan_typeplan
0Plan with Metrics<span style="white-space:pre-wrap;"> ProjectionExec: expr=[room@0 as room, AVG(home.temp)@1 as temp], metrics=[output_rows=2, elapsed_compute=4.768µs] </span>
<span style="white-space:pre-wrap;"> AggregateExec: mode=FinalPartitioned, gby=[room@0 as room], aggr=[AVG(home.temp)], ordering_mode=Sorted, metrics=[output_rows=2, elapsed_compute=140.405µs] </span>
<span style="white-space:pre-wrap;"> CoalesceBatchesExec: target_batch_size=8192, metrics=[output_rows=2, elapsed_compute=6.821µs] </span>
<span style="white-space:pre-wrap;"> 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] </span>
<span style="white-space:pre-wrap;"> AggregateExec: mode=Partial, gby=[room@0 as room], aggr=[AVG(home.temp)], ordering_mode=Sorted, metrics=[output_rows=2, elapsed_compute=137.577µs] </span>
<span style="white-space:pre-wrap;"> 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] </span>
<span style="white-space:pre-wrap;"> ProjectionExec: expr=[room@0 as room, temp@2 as temp], metrics=[output_rows=46, elapsed_compute=3.102µs] </span>
<span style="white-space:pre-wrap;"> CoalesceBatchesExec: target_batch_size=8192, metrics=[output_rows=46, elapsed_compute=25.585µs] </span>
<span style="white-space:pre-wrap;"> FilterExec: time@1 >= 1672531200000000000 AND time@1 <= 1703980800000000000, metrics=[output_rows=46, elapsed_compute=26.51µs] </span>
<span style="white-space:pre-wrap;"> 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] </span>

{{% /expand %}} {{< /expand-wrapper >}}

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 EXPLAIN report--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 ExecutionPlan node is added or removed, and how InfluxDB optimizes the query.

Example EXPLAIN ANALYZE VERBOSE

SQL
EXPLAIN ANALYZE VERBOSE SELECT temp FROM home
WHERE time >= now() - INTERVAL '7 days' AND room = 'Kitchen'
ORDER BY time