Updated memory guidelines and feedback docs to explicitly classify intra-partition phases as parallel, correcting prior assumptions of sequential execution. Refactored merge_layer.rs to wrap column builders in Arc<Mutex<ColBuilder>> and use Arc::try_unwrap for safe concurrent access, eliminating race conditions and preventing double-closes during pass2.
This change enhances observability and adaptability in the merge pipeline. Performance timing and debug logging are added to the De Bruijn graph and partition merge layers to track phase durations and pipeline metrics. The merge module replaces blocking receives with timed polls to sample CPU efficiency, dynamically spawning workers when utilization drops below a threshold. A new script is also introduced to parse merge debug logs and generate structured Markdown reports detailing throughput, phase breakdowns, and partition performance.