keys

const (
	// MetadataPrefix is the prefix for user metadata keys stored in RocksDB.
	// This ensures user keys have their own namespace separate from internal keys.
	// Uses the same format as other internal keys (starting with !)
	MetadataPrefix = "!meta/"

	// VersionHWMKey stores the durable version-reservation high-water mark for
	// the CAS stamp source (issue #254): nextVersion never issues a stamp above
	// the persisted reservation without first extending it durably, so stamps
	// stay monotonic across restarts even if the wall clock steps backward.
	// A single internal key; pre-versioning binaries simply never read it.
	VersionHWMKey = "!verhwm"

	// AccessBucketPrefix is the prefix for time-bucketed access index entries
	// Format: !access_bucket/YYYYMMDDHH/timestamp_nano/key
	AccessBucketPrefix = "!access_bucket/"

	// AccessBucketFormat is the time format for bucket keys (YYYYMMDDHH)
	AccessBucketFormat = "2006010215"

	// AccessBucketIndexPrefix is the prefix for the secondary index mapping keys to their bucket location
	// Format: !bucket_index/<key> -> bucketed_key
	AccessBucketIndexPrefix = "!access_bucket_index/"

	// CompactionIndexPrefix is the prefix for all compaction index entries in RocksDB
	CompactionIndexPrefix = "!compact/"

	// CompactionIndexKeyFormat is the format for compaction index keys
	// Format: !compact/<timestamp>|<userKey>
	CompactionIndexKeyFormat = "!compact/%020d|%s"

	// SyncIndexPrefix is the prefix for all sync tracking entries in RocksDB
	SyncIndexPrefix = "!sync/"

	// DeletionQueuePrefix is the prefix for deletion queue entries in RocksDB
	DeletionQueuePrefix = "!del/"

	// DeleteIndexPrefix is the prefix for segment deletion tracking entries in RocksDB
	DeleteIndexPrefix = "!delete:segment/"

	// FifoIndexPrefix is the prefix for the FIFO eviction index. Entries embed the
	// write time in the key so the eviction scan can walk them oldest-written
	// first. Unlike the access index, entries are written once at Put and never
	// bumped on reads.
	// Format: !fifo/<write_time_nano>/<key>
	FifoIndexPrefix = "!fifo/"

	// FifoBackrefPrefix is the prefix for the FIFO secondary index that maps a
	// cache key to its current FIFO entry, mirroring the LRU access index's
	// secondary index. It lets Put/Delete/TTL locate and remove a key's previous
	// FIFO entry so the index holds exactly one entry per live key.
	// Format: !fifo_ref/<key> -> !fifo/<nano>/<key>
	FifoBackrefPrefix = "!fifo_ref/"
)