MinTSOScheduler should schedule all the related mpp tasks if a query exceed hard limit
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- Dominant language
- C++
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Description
Enhancement
In MinTSOScheduler, if a mpp task is in waiting task set, and meet hard limit, it will schedule the task as EXCEEDED.
https://github.com/pingcap/tiflash/blob/4ab1564a17c2ed8bd78b5255f721def878fdd296/dbms/src/Flash/Mpp/MinTSOScheduler.cpp#L218
However, for all the other mpp tasks belong to the same query, the scheduler just leave them in the waiting task set, it makes the other mpp tasks' running thread hangs on waiting for schedule.
As an enhancement, once the scheduler found a mpp task exceed it's hard limit, it should schedule all the related mpp tasks as EXCEEDED
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Research direction
Start in dbms/src/Flash/Mpp/MinTSOScheduler.cpp around line 218 and trace how a waiting MPP task is marked EXCEEDED. Check how tasks are associated with a query and whether related-task scheduling has tests. Done means all related MPP tasks are scheduled as EXCEEDED when one task reaches its hard limit, without leaving other tasks waiting.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- distributed-systems
- Issue type
- Feature
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100