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Label: Internal. Do not depend on these layouts from applications; they are documented for contributors.
Physical#
physical.rs: PageHeader{magic,version,type,page_id,generation,lsn,payload_len,flags,checksum}, BlockMetadata, PackHeader/Footer, PhysicalLocation{device,pack,block,page,offset} with alignment validation. Managers: page_manager (PLPM), block_manager (PLBM, 16-page alloc), pack_manager (PLPK/PLPD/PLPF + BlockDirectoryEntry), device/* (PLDV/PLEX, extents, capacity reserve).
Row codec and B-tree#
row.rs: PR magic, v1, flags, field_count u16, null_bitmap, total_length u32; fields Integer(tag1+i64LE) | Bytes | String, NULL via bitmap; must fit PAGE_DATA_SIZE. btree.rs: page0 PLRT root pointer; nodes PLBT LEAF/INTERNAL; byte-midpoint split; no delete rebalance; in-place leaf upsert; get/range/insert/replace_if_present/delete/sync.
StorageManager: each segment an independent on-disk B-tree page file; newest Active, older Sealed; get newest-first; apply_batch routes via key_segments + sealed negative filter; replace_if_present in sealed before active upsert; rotate() at is_full. Segment wraps B-tree + XOR/roaring may_contain built lazily at seal. Placement via DeviceAllocator::select_device + round_up_to_extent.
Buffer pool and checksums#
buffer_pool.rs: single-threaded LRU, capacity frames, &mut-only; dirty write-through on evict; pinned_structural pages never evicted (leave only via sync); miss path verifies CRC + id. Checksums: CRC32C Castagnoli (crates/crc32c, KAT crc("123456789")==0xe3069283); page header CRC + whole-page trailer CRC; same primitive for pack/block/catalog (PLCT)/generation (PLGN)/checkpoint (PLCK)/WAL (PLW2)/columnar/roaring (PLRB)/XOR (PLXF)/segment (PLWS). Corruption → ErrorKind::Corruption.
Catalog#
catalog.rs: immutable CatalogState{version,generation,storage_gen,checkpoint_lsn,publication,records sorted by ObjectId}; ObjectRecord{object_id, table_identity, schema{columns{column_id,type_code}}, current_generation, retained_generations, references{PhysicalReference}, publication: Staged|Published|Retired}; 72 B PLCT v2 header, atomic publish, discovery ignores non-canonical names.