fix get node to read (#4663)

read when ts is equal

Approved by: @XuPeng-SH, @fengttt

pkg/vm/engine/tae/catalog/base.go

@@ -208,7 +208,7 @@ func (be *BaseEntry) GetNodeToRead(startts types.TS) (node *UpdateNode) {
 			}
 			return true
 		}
-		if un.End.Less(startts) {
+		if un.End.LessEq(startts) {
 			node = un
 			return false
 		}

pkg/vm/engine/tae/catalog/catalog.go

@@ -658,6 +658,12 @@ func (catalog *Catalog) CreateDBEntry(name string, txnCtx txnif.AsyncTxn) (*DBEn
 	return entry, err
 }
 
+func (catalog *Catalog) CreateDBEntryByTS(name string, ts types.TS) (*DBEntry, error) {
+	entry := NewDBEntryByTS(catalog, name, ts)
+	err := catalog.AddEntryLocked(entry, nil)
+	return entry, err
+}
+
 func (catalog *Catalog) RecurLoop(processor Processor) (err error) {
 	dbIt := catalog.MakeDBIt(true)
 	for dbIt.Valid() {

pkg/vm/engine/tae/catalog/database.go

@@ -94,6 +94,22 @@ func NewDBEntry(catalog *Catalog, name string, txnCtx txnif.AsyncTxn) *DBEntry {
 	return e
 }
 
+func NewDBEntryByTS(catalog *Catalog, name string, ts types.TS) *DBEntry {
+	id := catalog.NextDB()
+
+	e := &DBEntry{
+		BaseEntry: NewBaseEntry(id),
+		catalog:   catalog,
+		name:      name,
+		entries:   make(map[uint64]*common.DLNode),
+		nameNodes: make(map[string]*nodeList),
+		link:      new(common.SortedDList),
+	}
+	e.CreateWithTS(ts)
+	e.acInfo.CreateAt = types.CurrentTimestamp()
+	return e
+}
+
 func NewSystemDBEntry(catalog *Catalog) *DBEntry {
 	id := SystemDBID
 	entry := &DBEntry{

pkg/vm/engine/tae/db/db_test.go

@@ -2666,6 +2666,20 @@ func TestDropCreated2(t *testing.T) {
 	tae.restart()
 }
 
+// records create at 1 and commit
+// read by ts 1, err should be nil
+func TestReadEqualTS(t *testing.T) {
+	opts := config.WithLongScanAndCKPOpts(nil)
+	tae := newTestEngine(t, opts)
+	defer tae.Close()
+
+	txn, err := tae.StartTxn(nil)
+	tae.Catalog.CreateDBEntryByTS("db", txn.GetStartTS())
+	assert.Nil(t, err)
+	_, err = txn.GetDatabase("db")
+	assert.Nil(t, err)
+}
+
 func TestTruncateZonemap(t *testing.T) {
 	type Mod struct {
 		offset int