time of buildCopTask should be recorded into RuntimeStatistics
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- Dominant language
- Go
- Stars
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Description
Enhancement
The most time-consuming part of buildCopTasks is loading region cache. When there is a mass of regions metadata needs to be loaded, buildCopTasks will spend a lot of time. But we have no way to track this part of time except the log message like [2022/05/31 11:10:05.946 +08:00] [WARN] [coprocessor.go:232] ["buildCopTasks takes too much time"] [elapsed=10.001662187s] ["range len"=1] ["task len"=1].
This may pose a problem that we find a slow sql, but we can not figure out why even if we get the slow log and explain analyze.
We need to record this part of time consumption into the RuntimeStatistics.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start in store/copr/coprocessor.go at buildCopTasks and trace how its elapsed time relates to RuntimeStatistics. Review the existing slow-log message and the slow log and EXPLAIN ANALYZE context described in the issue. Done means the time spent by buildCopTasks, including region-cache loading, is available through RuntimeStatistics.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- go
- Domain
- database, performance
- Issue type
- Feature
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100