Flush Pipeline

The complete sequence from frozen memtable to durable S3 state.

Flow

Loading diagram...

Failure Modes

Crash Point	S3 State	Recovery
During build	Unchanged	WAL replay rebuilds memtable
During upload	Incomplete multipart	S3 lifecycle aborts it. WAL replay.
During CAS	SSTable on S3, not in manifest	Orphan GC deletes it. WAL replay.
After CAS, before WAL cleanup	Manifest updated, WAL intact	WAL replay is idempotent

The WAL is the safety net. The manifest CAS is the commit point.