{"id":"truncate-advances-base-offset-additively","text":"`Topic.truncate` updates `_base_offsets[partition]` with `+= actual`, a relative shift, because it only removes a contiguous prefix from the front of the partition log.","truth_value":"IN","source":"entries/2026/05/29/topic-log-compaction-vs-retention.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"truncate-advances-base-offset-additively","truth_value":"IN","reason":"premise"}]}}