a-b-street/abstreet

Smaller files: don't serialize turn geometry?

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#94 opened on Jun 24, 2020

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 (5 comments) (1 reaction) (0 assignees)Rust (6,779 stars) (256 forks)batch import
good first issue

Description

Not sure this will work, but it's a good little exploratory project. map_model/src/turn.rs stores geom: PolyLine. Last time I used the serialized_size_bytes stuff in map.rs, these polylines constituted a huge part of the binary map files. The release size is slowly growing, so it'd be nice to trim this down.

Maybe we could skip serializing the PolyLine, then in Map::new after deserializing, go fill it in again. Should measure the impact on file sizes and initial map loading time.

Contributor guide

Tech stack
rust
Domain
performancedata
Issue type
performance
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Rust programmingSerde serializationmap model structure
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Explore the serialization of PolyLine in map model/src/turn.rs. Measure the size impact using serialized size bytes in map.rs. Implement skipping serialization of the PolyLine field and regenerate it in Map::new. Test file size and loading time changes.