Critical fixes:
- B-Tree splitChild: fixed out-of-bounds on child.children.len (mid+1..len → mid+1..<len)
- Wire protocol: all deserializeValue cases now properly assign to result
- Wire protocol: fkBool/fkInt8 now increment pos after reading
- MVCC: write-write conflict now detected for completed transactions
- MVCC: commit only marks visible versions as deleted (not concurrent uncommitted)
- Lexer: buffer overrun on backslash escape at end of input — added bounds check
- Bulgarian/Russian stemmers: fixed UTF-8 byte offsets for Cyrillic suffixes (2 bytes per char)
High fixes:
- WebSocket: added missing std/tables import
- Raft: added randomize() call for election timeouts
- MemTable.get: binary search O(log n) instead of linear scan O(n)
Medium fixes:
- Zerocopy: string length now written as 4-byte int32 (was single byte)
- Raft appendEntries: guard against nextIdx underflow
- Columnar: null tracking with nulls seq on ColumnPtr
- Removed dead code in lexer readIdent (redundant true/false checks)
- Updated Bulgarian stemming test to match corrected byte offsets
All 214 tests pass across 48 suites with 0 failures.
Zero-Copy Serialization:
- Direct memory buffer with schema-based field offsets
- Write/read int32/int64/float/bool/string without copies
- FastMem copy operations (fastCopy, fastCopyFrom, slice)
- ZcTable for batch columnar records
Adaptive Query Execution:
- Cardinality estimation with exponential moving average
- Reoptimize triggers when actual/estimated row ratio exceeds threshold
- Plan caching with hash-based lookup
- Execution context with parallelism hints and explain
Distributed Transactions:
- Two-phase commit across multiple nodes
- Saga pattern with step-by-step execute/compensate
- DistTxnManager with cleanup lifecycle
Vector Batch Operations:
- batchInsert/batchSearch for HNSW and IVF-PQ
- IndexWatcher with auto-rebuild based on unindexed count and ratio
- Rebuild statistics tracking
26 new tests (222 total, all passing)