clockworklabs / clockworklabs/SpacetimeDB
perf: Shrink `Table` by `Box`ing the `colliders` and `emptied_collider_slots` in `PointerMap`
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- Dominant language
- Rust
- Stars
- 25.2k
- Forks
- 1.1k
- Avg merge
- 2d 7h
- Merged PRs (30d)
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Description
This shaves off 40 bytes from PointerMap and in turn from Table.
Boxing here is not a problem as collisions are rare.
The perf impact of this hasn't been measured, but large types in general impose memcpys instead of using registers.
We should fix this once the more glaring issues have been resolved.
Contributor guide
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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
Locate the definitions of PointerMap and Table, then inspect the colliders and emptied_collider_slots fields and their uses. Compare the resulting type layout and verify that the intended 40-byte reduction is achieved without breaking collision handling; the issue notes that performance impact has not yet been measured.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- databases, performance
- Issue type
- Refactor
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100