| # BE Storage Module — Review Guide |
| |
| ## Tablet Locks |
| |
| | Lock | Type | Role | |
| |------|------|------| |
| | `_meta_lock` | `shared_mutex` | Version maps and tablet metadata visibility | |
| | `_rowset_update_lock` | `mutex` | Serializes delete bitmap updates (publish / MoW) | |
| | `_base_compaction_lock` | `mutex` | Serializes base compaction | |
| | `_cumulative_compaction_lock` | `mutex` | Serializes cumulative compaction | |
| |
| ### Checkpoints |
| |
| - [ ] `_rs_version_map` and `_stale_rs_version_map` accessed under `_meta_lock` with correct shared/exclusive mode? |
| - [ ] Tablet-meta mutations under exclusive `_meta_lock`? |
| - [ ] Nested locking follows established preconditions? (`update_delete_bitmap_without_lock()` requires both `_rowset_update_lock` and `_meta_lock`) |
| - [ ] TxnManager lock order: `_txn_lock → _txn_map_lock`? |
| |
| ## Rowset and Version Lifecycle |
| |
| - [ ] `add_rowset()` / `modify_rowsets()` under exclusive `_meta_lock`? |
| - [ ] Version continuity preserved, or intentional same-version replacement used correctly? |
| - [ ] Same-version replacement: old rowset moved to unused-rowset tracking before new becomes authoritative? |
| - [ ] Reader/rowset code respects split lifetime: `shared_ptr` ownership + reader `acquire()` / `release()`? |
| - [ ] `StorageEngine::_unused_rowsets` deletable only when `use_count() == 1`? |
| |
| ## Delete Bitmap (MoW) |
| |
| - [ ] Cloud mode: `TEMP_VERSION_COMMON` and sentinels replaced before bitmap use? |
| - [ ] Bitmap calculation serialized under `_rowset_update_lock`? |
| - [ ] Compaction bitmap uses latest compaction counters, not stale snapshots? |
| |
| ## Segment Writing |
| |
| - [ ] MoW tables: `SegmentWriterOptions::enable_unique_key_merge_on_write` set to `true` on every path? |
