Add MsgBlock write cache (mirrors Go's msgBlock.cache) to serve reads
for recently-written records without disk I/O; cleared on block seal via
RotateBlock. Add HashWheel-based TTL expiry in FileStore (ExpireFromWheel /
RegisterTtl), replacing the O(n) linear scan on every append with an
O(expired) wheel scan. Implement StoreMsg sync method with per-message TTL
override support. Add 10 tests covering cache hits/eviction, wheel expiry,
retention, StoreMsg seq/ts, per-msg TTL, and recovery re-registration.
Implement PurgeEx, Compact, Truncate, FilteredState, SubjectsState,
SubjectsTotals, State, FastState, GetSeqFromTime on FileStore. Add
MsgBlock.IsDeleted, DeletedSequences, EnumerateNonDeleted. Includes
wildcard subject support via SubjectMatch for all filtered operations.
Replace JSONL persistence with real MsgBlock-based block files (.blk).
FileStore now acts as a block manager that creates, seals, and rotates
MsgBlocks while maintaining an in-memory cache for fast reads/queries.
Key changes:
- AppendAsync writes transformed payloads to MsgBlock via WriteAt
- Block rotation occurs when active block reaches size limit
- Recovery scans .blk files and rebuilds in-memory state from records
- Legacy JSONL migration: existing messages.jsonl data is automatically
converted to block files on first open, then JSONL is deleted
- PurgeAsync disposes and deletes all block files
- RewriteBlocks rebuilds blocks from cache (used by trim/restore)
- InvalidDataException propagates during recovery (wrong encryption key)
MsgBlock.WriteAt added to support explicit sequence numbers and timestamps,
needed when rewriting blocks with non-contiguous sequences (after removes).
Tests updated:
- New FileStoreBlockTests.cs with 9 tests for block-specific behavior
- JetStreamFileStoreCompressionEncryptionParityTests updated to read
FSV1 magic from .blk files instead of messages.jsonl
- JetStreamFileStoreDurabilityParityTests updated to verify .blk files
instead of index.manifest.json
All 3,562 tests pass (3,535 passed + 27 skipped, 0 failures).
MsgBlock is the unit of storage in the file store — a single append-only
block file containing sequentially written binary message records. Blocks
are sealed (read-only) when they reach a configurable byte-size limit.
Key features:
- Write: appends MessageRecord-encoded messages with auto-incrementing
sequence numbers and configurable first sequence offset
- Read: positional I/O via RandomAccess.Read for concurrent reader safety
- Delete: soft-delete with on-disk persistence (re-encodes flags byte +
checksum so deletions survive recovery)
- Recovery: rebuilds in-memory index by scanning block file using
MessageRecord.MeasureRecord for record boundary detection
- Thread safety: ReaderWriterLockSlim allows concurrent reads during writes
Also adds MessageRecord.MeasureRecord() — computes a record's byte length
by parsing varint field headers without full decode, needed for sequential
record scanning during block recovery.
Reference: golang/nats-server/server/filestore.go:217-267 (msgBlock struct)
12 tests covering write, read, delete, seal, recovery, concurrency,
and custom sequence offsets.
Add MessageRecord class with Encode/Decode for the binary wire format
used in JetStream file store blocks. Uses varint-encoded lengths,
XxHash64 checksums, and a flags byte for deletion markers.
Go reference: filestore.go:6720-6724, 8180-8250, 8770-8777
13 tests covering round-trip, headers, checksum validation, corruption
detection, varint encoding, deleted flag, empty/large payloads.
Replace Deflate+XOR with IronSnappy S2 block compression and ChaCha20-Poly1305 / AES-256-GCM
AEAD encryption, matching golang/nats-server/server/filestore.go. Introduces FSV2 envelope
format alongside existing FSV1 for backward compatibility. Adds 55 new tests across
S2CodecTests, AeadEncryptorTests, and FileStoreV2Tests covering all 6 cipher×compression
permutations, tamper detection, and legacy format round-trips.
Stream lifecycle, publish/ack, consumer delivery, retention policy,
API endpoints, cluster formation, and leader failover tests ported
from Go nats-server reference. 1006 total tests passing.
