refactor: reduce watchmap memory size#92
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wolfv merged 1 commit intoprefix-dev:mainfrom Jan 2, 2025
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Reduce the memory consumption of the
WatchMapby utilizingNonZeroU32. Rust has an optimization that anOption<NonZero..>is the same size as aNonZero... The optimization uses the fact that0meansNone.Our
Mappingtype storesOption<T>. TheWatchMapcontains aMapping<Literal, ClauseId>. For eachLiteralwe store anOption<ClauseId>. Previously we would encode anullclause asClauseId::null. We now store this as anOption<ClauseId>.This reduces the memory size of an
Option<ClauseId>from 8 bytes to 4 bytes. It reduces the memory usage of the watchmap by 50% and makes working with a null clause more ergonomic.I didnt run the benchmarks but I am quite confident that there will be no negative impact.