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ab94d6dc18
Co-authored-by: Nikita Taranov <nikita.taranov@clickhouse.com>
4.7 KiB
4.7 KiB
system.processors_profile_log
This table contains profiling on processors level (that you can find in EXPLAIN PIPELINE
).
Columns:
event_date
(Date) — The date when the event happened.event_time
(DateTime64) — The date and time when the event happened.id
(UInt64) — ID of processorparent_ids
(Array(UInt64)) — Parent processors IDsquery_id
(String) — ID of the queryname
(LowCardinality(String)) — Name of the processor.elapsed_us
(UInt64) — Number of microseconds this processor was executed.input_wait_elapsed_us
(UInt64) — Number of microseconds this processor was waiting for data (from other processor).output_wait_elapsed_us
(UInt64) — Number of microseconds this processor was waiting because output port was full.plan_step
(UInt64) — ID of the query plan step which created this processor. The value is zero if the processor was not added from any step.plan_group
(UInt64) — Group of the processor if it was created by query plan step. A group is a logical partitioning of processors added from the same query plan step. Group is used only for beautifying the result of EXPLAIN PIPELINE result.input_rows
(UInt64) — The number of rows consumed by processor.input_bytes
(UInt64) — The number of bytes consumed by processor.output_rows
(UInt64) — The number of rows generated by processor.output_bytes
(UInt64) — The number of bytes generated by processor. Example
Query:
EXPLAIN PIPELINE
SELECT sleep(1)
┌─explain─────────────────────────┐
│ (Expression) │
│ ExpressionTransform │
│ (SettingQuotaAndLimits) │
│ (ReadFromStorage) │
│ SourceFromSingleChunk 0 → 1 │
└─────────────────────────────────┘
SELECT sleep(1)
SETTINGS log_processors_profiles = 1
Query id: feb5ed16-1c24-4227-aa54-78c02b3b27d4
┌─sleep(1)─┐
│ 0 │
└──────────┘
1 rows in set. Elapsed: 1.018 sec.
SELECT
name,
elapsed_us,
input_wait_elapsed_us,
output_wait_elapsed_us
FROM system.processors_profile_log
WHERE query_id = 'feb5ed16-1c24-4227-aa54-78c02b3b27d4'
ORDER BY name ASC
Result:
┌─name────────────────────┬─elapsed_us─┬─input_wait_elapsed_us─┬─output_wait_elapsed_us─┐
│ ExpressionTransform │ 1000497 │ 2823 │ 197 │
│ LazyOutputFormat │ 36 │ 1002188 │ 0 │
│ LimitsCheckingTransform │ 10 │ 1002994 │ 106 │
│ NullSource │ 5 │ 1002074 │ 0 │
│ NullSource │ 1 │ 1002084 │ 0 │
│ SourceFromSingleChunk │ 45 │ 4736 │ 1000819 │
└─────────────────────────┴────────────┴───────────────────────┴────────────────────────┘
Here you can see:
ExpressionTransform
was executingsleep(1)
function, so itwork
will takes 1e6, and soelapsed_us
> 1e6.SourceFromSingleChunk
need to wait, becauseExpressionTransform
does not accept any data during execution ofsleep(1)
, so it will be inPortFull
state for 1e6 us, and sooutput_wait_elapsed_us
> 1e6.LimitsCheckingTransform
/NullSource
/LazyOutputFormat
need to wait untilExpressionTransform
will executesleep(1)
to process the result, soinput_wait_elapsed_us
> 1e6.
See Also