Reduce virtual function call overhead for constructing columns in join probing
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type/enhancement
- Dominant language
- C++
- Stars
- 1k
- Forks
- 423
- Avg merge
- 1d 15h
- Merged PRs (30d)
- 24
Description
Enhancement
During join probing, some codes like the below call virtual function for each row. We can reduce this overhead through batching.
https://github.com/pingcap/tiflash/blob/7779b00f2933d0d4fa21bd5d8904736948f24e5c/dbms/src/Interpreters/JoinPartition.cpp#L1313-L1318
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Research direction
Start in dbms/src/Interpreters/JoinPartition.cpp at lines 1313-1318 and inspect how join probing constructs columns for each row. Determine how batching could replace the per-row virtual calls, then verify that column construction during join probing no longer incurs that overhead.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- backend, performance
- Issue type
- Refactor
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100