refactor(storage): MemTable 更名为 Engine，跳表拆出独立文件

cmd/ban-ingest/main.go

@@ -90,7 +90,7 @@ type Result struct {
 }
 
 // setupEngine 指向临时目录并以小 memtable 创建引擎，返回引擎与清理函数。
-func setupEngine(memTableSize int) (*storage.MemTable, func()) {
+func setupEngine(memTableSize int) (*storage.Engine, func()) {
 	tmp, err := os.MkdirTemp("", "bandb-ingest-*")
 	if err != nil {
 		panic(err)
@@ -99,7 +99,7 @@ func setupEngine(memTableSize int) (*storage.MemTable, func()) {
 	config.G.WALPath = filepath.Join(tmp, "wal.log")
 	config.G.MaxMemTableSize = memTableSize
 
-	memTable := storage.NewMemTable()
+	memTable := storage.NewEngine()
 	cleanup := func() {
 		_ = memTable.Close()
 		os.RemoveAll(tmp)
@@ -108,7 +108,7 @@ func setupEngine(memTableSize int) (*storage.MemTable, func()) {
 }
 
 // memSampler 每 100ms 采样一次堆内存与未 flush 字节信用，返回停止函数（调用后回填峰值）。
-func memSampler(mt *storage.MemTable, heapPeak, sysPeak, inflightPeak *uint64) func() {
+func memSampler(mt *storage.Engine, heapPeak, sysPeak, inflightPeak *uint64) func() {
 	stop := make(chan struct{})
 	var wg sync.WaitGroup
 	wg.Add(1)

service/fsm.go

@@ -35,7 +35,7 @@ type Command struct {
 
 type KVServer struct {
 	raft    *raft.Raft
-	storage *storage.MemTable
+	storage *storage.Engine
 	wal     *storage.WAL // standalone 模式的存储层 WAL；raft 模式为 nil
 
 	// cpMu 协调写入与 WAL checkpoint：每次写用 RLock 把 wal.Append+storage.Put
@@ -52,7 +52,7 @@ type KVServer struct {
 func NewKVServer() *KVServer {
 	// 初始化存储
 	kv := &KVServer{
-		storage: storage.NewMemTable(),
+		storage: storage.NewEngine(),
 	}
 
 	if config.G.Mode == config.ModeStandalone {

storage/bench_test.go

@@ -10,7 +10,7 @@ import (
 
 func benchmarkEnginePut(b *testing.B, valueSize int) {
 	config.G.MaxMemTableSize = 1000000 // prevent flush during bench
-	memTable := storage.NewMemTable()
+	memTable := storage.NewEngine()
 
 	value := make([]byte, valueSize)
 	for i := range value {
@@ -31,7 +31,7 @@ func BenchmarkEngine_Put_4KB(b *testing.B)  { benchmarkEnginePut(b, 4096) }
 
 func BenchmarkEngine_Get(b *testing.B) {
 	config.G.MaxMemTableSize = 1000000
-	memTable := storage.NewMemTable()
+	memTable := storage.NewEngine()
 
 	value := make([]byte, 256)
 	for i := 0; i < 10000; i++ {
@@ -48,7 +48,7 @@ func BenchmarkEngine_Get(b *testing.B) {
 
 func BenchmarkEngine_Delete(b *testing.B) {
 	config.G.MaxMemTableSize = 1000000
-	memTable := storage.NewMemTable()
+	memTable := storage.NewEngine()
 
 	value := make([]byte, 256)
 	keys := make([][]byte, b.N)
@@ -65,7 +65,7 @@ func BenchmarkEngine_Delete(b *testing.B) {
 
 func BenchmarkMemTable_Put(b *testing.B) {
 	config.G.MaxMemTableSize = 1000000
-	mt := storage.NewMemTable()
+	mt := storage.NewEngine()
 	value := []byte("benchmark-value-data-256-bytes-padding-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")
 
 	b.ResetTimer()
@@ -77,7 +77,7 @@ func BenchmarkMemTable_Put(b *testing.B) {
 
 func BenchmarkMemTable_Get(b *testing.B) {
 	config.G.MaxMemTableSize = 1000000
-	mt := storage.NewMemTable()
+	mt := storage.NewEngine()
 	value := []byte("benchmark-value")
 	for i := 0; i < 100000; i++ {
 		key := []byte(fmt.Sprintf("key-%08d", i))

storage/compaction_bench_test.go

@@ -24,7 +24,7 @@ func TestCompactionBench(t *testing.T) {
 
 	ResetCompactionStats()
 
-	// 不经 NewMemTable（避免启动异步 FlushWorker/ListenCompactCh 造成非确定性），
+	// 不经 NewEngine（避免启动异步 FlushWorker/ListenCompactCh 造成非确定性），
 	// 只用 sst，手动驱动 flush 与 compaction。
 	mt := newBareMemTable(NewSSTable())