Module flush 

Memtable freeze-and-flush mechanism.

This module implements the lifecycle of a memtable: freeze the active memtable (making it immutable), swap in a fresh one, flush the frozen memtable to a segment file via SegmentWriter, and optionally truncate the WAL up to the flushed sequence number.

Flush triggers

Flush is triggered when:

• estimated_size > memtable_flush_threshold
• A time-shard boundary is crossed

Memory bounds

If the combined size of active + frozen memtables exceeds max_memtable_memory, new inserts are rejected with MemtableError::CapacityExceeded.

Structs

FlushConfig

Configuration for the flush controller.

FlushController

Manages the active and frozen memtable lifecycle.

FlushResult

Result of a flush operation for a single measurement.