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unexpectedly long query run time

Open PsiACE opened this issue 2 years ago • 2 comments

Typically, most queries on the ontime dataset can be completed in less than 1 second.

However, in several recent performance tests, some statements may experience severe timeouts, even taking tens of minutes, until jwt expired.

query expected actual history
SELECT DayOfWeek, count(*) AS c FROM default.ontime WHERE DepDelay>10 AND Year >= 2000 AND Year <= 2008 GROUP BY DayOfWeek ORDER BY c DESC; < 0.5s 42min
SELECT IATA_CODE_Reporting_Airline AS Carrier, avg(DepDelay) * 1000 AS c3 FROM default.ontime WHERE Year >= 2000 AND Year <= 2008 GROUP BY Carrier; < 1s > 60min https://github.com/datafuselabs/databend-perf/runs/7172566428?check_suite_focus=true
SELECT IATA_CODE_Reporting_Airline AS Carrier, avg(cast(DepDelay\u003e10 as Int8))*1000 AS c3 FROM default.ontime WHERE Year\u003e=2000 AND Year \u003c=2008 GROUP BY Carrier ORDER BY c3 DESC; <0.5s https://github.com/datafuselabs/databend-perf/runs/7159465292?check_suite_focus=true

PsiACE avatar Jul 04 '22 03:07 PsiACE

It may be necessary to check if there is a scheduling problem, or if there is some other fault with the databend.

PsiACE avatar Jul 04 '22 03:07 PsiACE

it looks like these queries get slow again.

flaneur2020 avatar Aug 23 '22 05:08 flaneur2020