wave4-native-parallel-multihashmap-parallel-writer

To insert into a NativeParallelMultiHashMap from multiple parallel jobs, call AsParallelWriter() on the map and pass the writer into your Burst job. This enables lock-free concurrent additions across worker threads without race conditions.

Lock-free spatial hashing is achieved by using NativeParallelMultiHashMap with AsParallelWriter. Multiple worker threads safely scatter entity indices into spatial buckets concurrently, followed by a sequential gather stage to read the results.

You cannot read from the map using the parallel writer. Thread-safety requirements restrict reads to non-parallel access, meaning you must schedule a separate subsequent job to gather and process the inserted values sequentially.

AsParallelWriter works with NativeParallelMultiHashMap to support multi-value buckets. When multiple threads insert entries with the same key, the writer safely chains the values together, enabling scatter-gather workflows for grouping entities.

Parallel inserts fail when the map lacks adequate capacity. You must enforce sufficient capacity using the appropriate allocator before scheduling jobs, ensuring the map has enough memory for all concurrent entries added by worker threads.