Module compaction 

Compaction Isolation

This module provides per-shard compaction queues that allow background index rebuilding without blocking readers.

Problem

Global compaction blocks all shards:

• Lock contention during CSR rebuild
• Readers stall waiting for compaction
• Unpredictable latency spikes

Solution

Per-shard compaction with version-based isolation:

1. Each shard has independent compaction queue
2. Build new CSR/AoSoA in background
3. Atomic pointer swap when ready
4. Old version kept until readers drain (epoch-based reclamation)

Invariants

• Readers never block on compaction
• Writers queue updates for next compaction cycle
• At most one compaction per shard at a time
• Compaction preserves search correctness

Structs

CompactionConfig

Compaction configuration.

CompactionQueue

Compaction queue manager for multiple shards.

CompactionResult

Result of a compaction operation.

CompactionStats

Compaction statistics.

CompactionTask

Compaction task for a shard.

CompactionWorker

Background compaction worker.

MockCompactionExecutor

Simple in-memory compaction executor for testing.

ReaderGuard

Guard that tracks reader lifetime.

ShardCompactionState

Per-shard compaction state.

Enums

CompactionPriority

Compaction priority levels.

Traits

CompactionExecutor

Trait for compaction executor.

Type Aliases

ShardId

Shard identifier for compaction.

Version

Version number for compacted data.