Auto indexing should be skipped if subset and modify are on the same column
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Assessment
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Newbie friendliness
- 35/100
Research direction
Start by reproducing the provided data.table expression and inspect when the index is created and then removed. Done means the subset-and-modify operation does not create an unnecessary index on the modified column, while the existing indexing behavior remains unchanged for other operations.
Written by the indexing model from the issue text.
Description
See this SO post for more info. Doing:
DT[y %in% 5:10, y := 100]
will create an index, and get modified, which results in the index getting removed, and as a result will be slow (due to creating the index unnecessarily every time) on bigger data.
- Dominant language
- R
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- Merged PRs (30d)
- 4
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