[#1431] pilorama: Cache attributes in the index

Currently to find a node by path we iterate over all the children on
each level. This is far from optimal and scales badly with the number of
nodes on a single level. Thus we introduce "indexed attributes" for
which an additional information is stored and which can be use in
`*ByPath` operations. Currently this set only includes `FileName`
attribute but this may change in future.

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>

pkg/local_object_storage/pilorama/boltdb.go

@@ -38,6 +38,7 @@ var (
 // 'p' + node (id) -> parent (id)
 // 'm' + node (id) -> serialized meta
 // 'c' + parent (id) + child (id) -> 0/1
+// 'i' + 0 + attrKey + 0 + attrValue + 0 + parent (id) + node (id) -> 0/1 (1 for automatically created nodes)
 func NewBoltForest(path string) ForestStorage {
 	return &boltForest{path: path}
 }
@@ -89,6 +90,10 @@ func (t *boltForest) TreeMove(cid cidSDK.ID, treeID string, m *Move) (*LogMove,
 
 // TreeAddByPath implements the Forest interface.
 func (t *boltForest) TreeAddByPath(cid cidSDK.ID, treeID string, attr string, path []string, meta []KeyValue) ([]LogMove, error) {
+	if !isAttributeInternal(attr) {
+		return nil, ErrNotPathAttribute
+	}
+
 	var lm []LogMove
 	var key [17]byte
 
@@ -273,7 +278,7 @@ func (t *boltForest) do(lb *bbolt.Bucket, b *bbolt.Bucket, key []byte, op *LogMo
 				return err
 			}
 		}
-		return t.removeNode(b, key, op.Child)
+		return t.removeNode(b, key, op.Child, op.Parent)
 	}
 
 	if currParent == nil {
@@ -281,18 +286,43 @@ func (t *boltForest) do(lb *bbolt.Bucket, b *bbolt.Bucket, key []byte, op *LogMo
 			return err
 		}
 	} else {
-		if err := b.Delete(childrenKey(key, op.Child, binary.LittleEndian.Uint64(currParent))); err != nil {
+		parent := binary.LittleEndian.Uint64(currParent)
+		if err := b.Delete(childrenKey(key, op.Child, parent)); err != nil {
 			return err
 		}
+		var meta Meta
+		var k = metaKey(key, op.Child)
+		if err := meta.FromBytes(b.Get(k)); err == nil {
+			for i := range meta.Items {
+				if isAttributeInternal(meta.Items[i].Key) {
+					err := b.Delete(internalKey(nil, meta.Items[i].Key, string(meta.Items[i].Value), parent, op.Child))
+					if err != nil {
+						return err
+					}
+				}
+			}
+		}
 	}
 	return t.addNode(b, key, op.Child, op.Parent, op.Meta)
 }
 
 // removeNode removes node keys from the tree except the children key or its parent.
-func (t *boltForest) removeNode(b *bbolt.Bucket, key []byte, node Node) error {
+func (t *boltForest) removeNode(b *bbolt.Bucket, key []byte, node, parent Node) error {
 	if err := b.Delete(parentKey(key, node)); err != nil {
 		return err
 	}
+	var meta Meta
+	var k = metaKey(key, node)
+	if err := meta.FromBytes(b.Get(k)); err == nil {
+		for i := range meta.Items {
+			if isAttributeInternal(meta.Items[i].Key) {
+				err := b.Delete(internalKey(nil, meta.Items[i].Key, string(meta.Items[i].Value), parent, node))
+				if err != nil {
+					return err
+				}
+			}
+		}
+	}
 	if err := b.Delete(metaKey(key, node)); err != nil {
 		return err
 	}
@@ -309,7 +339,27 @@ func (t *boltForest) addNode(b *bbolt.Bucket, key []byte, child, parent Node, me
 	if err != nil {
 		return err
 	}
-	return b.Put(metaKey(key, child), meta.Bytes())
+	err = b.Put(metaKey(key, child), meta.Bytes())
+	if err != nil {
+		return err
+	}
+
+	for i := range meta.Items {
+		if !isAttributeInternal(meta.Items[i].Key) {
+			continue
+		}
+
+		key = internalKey(key, meta.Items[i].Key, string(meta.Items[i].Value), parent, child)
+		if len(meta.Items) == 1 {
+			err = b.Put(key, []byte{1})
+		} else {
+			err = b.Put(key, []byte{0})
+		}
+		if err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func (t *boltForest) undo(m *Move, lm *LogMove, b *bbolt.Bucket, key []byte) error {
@@ -318,7 +368,7 @@ func (t *boltForest) undo(m *Move, lm *LogMove, b *bbolt.Bucket, key []byte) err
 	}
 
 	if !lm.HasOld {
-		return t.removeNode(b, key, m.Child)
+		return t.removeNode(b, key, m.Child, m.Parent)
 	}
 	return t.addNode(b, key, m.Child, lm.Old.Parent, lm.Old.Meta)
 }
@@ -338,6 +388,10 @@ func (t *boltForest) isAncestor(b *bbolt.Bucket, key []byte, parent, child Node)
 
 // TreeGetByPath implements the Forest interface.
 func (t *boltForest) TreeGetByPath(cid cidSDK.ID, treeID string, attr string, path []string, latest bool) ([]Node, error) {
+	if !isAttributeInternal(attr) {
+		return nil, ErrNotPathAttribute
+	}
+
 	if len(path) == 0 {
 		return nil, nil
 	}
@@ -360,40 +414,29 @@ func (t *boltForest) TreeGetByPath(cid cidSDK.ID, treeID string, attr string, pa
 			return nil
 		}
 
-		c := b.Cursor()
-
 		var (
-			metaKey      [9]byte
-			id           [9]byte
 			childID      [9]byte
-			m            Meta
 			maxTimestamp uint64
 		)
 
-		id[0] = 'c'
+		c := b.Cursor()
-		metaKey[0] = 'm'
 
-		binary.LittleEndian.PutUint64(id[1:], curNode)
+		attrKey := internalKey(nil, attr, path[len(path)-1], curNode, 0)
-
+		attrKey = attrKey[:len(attrKey)-8]
-		key, _ := c.Seek(id[:])
+		childKey, _ := c.Seek(attrKey)
-		for len(key) == 1+8+8 && bytes.Equal(id[:9], key[:9]) {
+		for len(childKey) == len(attrKey)+8 && bytes.Equal(attrKey, childKey[:len(childKey)-8]) {
-			child := binary.LittleEndian.Uint64(key[9:])
+			child := binary.LittleEndian.Uint64(childKey[len(childKey)-8:])
-			copy(metaKey[1:], key[9:17])
+			if latest {
-
+				ts := binary.LittleEndian.Uint64(b.Get(timestampKey(childID[:], child)))
-			if m.FromBytes(b.Get(metaKey[:])) == nil && string(m.GetAttr(attr)) == path[len(path)-1] {
+				if ts >= maxTimestamp {
-				if latest {
+					nodes = append(nodes[:0], child)
-					ts := binary.LittleEndian.Uint64(b.Get(timestampKey(childID[:], child)))
+					maxTimestamp = ts
-					if ts >= maxTimestamp {
-						nodes = append(nodes[:0], child)
-						maxTimestamp = ts
-					}
-				} else {
-					nodes = append(nodes, child)
 				}
+			} else {
+				nodes = append(nodes, child)
 			}
-			key, _ = c.Next()
+			childKey, _ = c.Next()
 		}
-
 		return nil
 	})
 }
@@ -470,36 +513,25 @@ func (t *boltForest) TreeGetOpLog(cid cidSDK.ID, treeID string, height uint64) (
 }
 
 func (t *boltForest) getPathPrefix(bTree *bbolt.Bucket, attr string, path []string) (int, Node, error) {
-	var key [9]byte
-
 	c := bTree.Cursor()
 
 	var curNode Node
-	var m Meta
+	var attrKey []byte
 
 loop:
 	for i := range path {
-		key[0] = 'c'
+		attrKey = internalKey(attrKey, attr, path[i], curNode, 0)
-		binary.LittleEndian.PutUint64(key[1:], curNode)
+		attrKey = attrKey[:len(attrKey)-8]
 
-		childKey, _ := c.Seek(key[:])
+		childKey, value := c.Seek(attrKey)
-		for {
+		for len(childKey) == len(attrKey)+8 && bytes.Equal(attrKey, childKey[:len(childKey)-8]) {
-			if len(childKey) != 17 || binary.LittleEndian.Uint64(childKey[1:]) != curNode {
+			if len(value) == 1 && value[0] == 1 {
-				break
+				curNode = binary.LittleEndian.Uint64(childKey[len(childKey)-8:])
-			}
-
-			child := binary.LittleEndian.Uint64(childKey[9:])
-			if err := m.FromBytes(bTree.Get(metaKey(key[:], child))); err != nil {
-				return 0, 0, err
-			}
-
-			// Internal nodes have exactly one attribute.
-			if len(m.Items) == 1 && m.Items[0].Key == attr && string(m.Items[0].Value) == path[i] {
-				curNode = child
 				continue loop
 			}
-			childKey, _ = c.Next()
+			childKey, value = c.Next()
 		}
+
 		return i, curNode, nil
 	}
 
@@ -581,6 +613,33 @@ func childrenKey(key []byte, child, parent Node) []byte {
 	return key[:17]
 }
 
+// 'i' + attribute name (string) + attribute value (string) + parent (id) + node (id) -> 0/1
+func internalKey(key []byte, k, v string, parent, node Node) []byte {
+	size := 1 /* prefix */ + 2*2 /* len */ + 2*8 /* nodes */ + len(k) + len(v)
+	if cap(key) < size {
+		key = make([]byte, 0, size)
+	}
+
+	key = key[:0]
+	key = append(key, 'i')
+
+	l := len(k)
+	key = append(key, byte(l), byte(l>>8))
+	key = append(key, k...)
+
+	l = len(v)
+	key = append(key, byte(l), byte(l>>8))
+	key = append(key, v...)
+
+	var raw [8]byte
+	binary.LittleEndian.PutUint64(raw[:], parent)
+	key = append(key, raw[:]...)
+
+	binary.LittleEndian.PutUint64(raw[:], node)
+	key = append(key, raw[:]...)
+	return key
+}
+
 func toUint64(x uint64) []byte {
 	var a [8]byte
 	binary.LittleEndian.PutUint64(a[:], x)

pkg/local_object_storage/pilorama/forest.go

@@ -43,6 +43,10 @@ func (f *memoryForest) TreeMove(cid cidSDK.ID, treeID string, op *Move) (*LogMov
 
 // TreeAddByPath implements the Forest interface.
 func (f *memoryForest) TreeAddByPath(cid cidSDK.ID, treeID string, attr string, path []string, m []KeyValue) ([]LogMove, error) {
+	if !isAttributeInternal(attr) {
+		return nil, ErrNotPathAttribute
+	}
+
 	fullID := cid.String() + "/" + treeID
 	s, ok := f.treeMap[fullID]
 	if !ok {
@@ -98,6 +102,10 @@ func (f *memoryForest) Close() error {
 
 // TreeGetByPath implements the Forest interface.
 func (f *memoryForest) TreeGetByPath(cid cidSDK.ID, treeID string, attr string, path []string, latest bool) ([]Node, error) {
+	if !isAttributeInternal(attr) {
+		return nil, ErrNotPathAttribute
+	}
+
 	fullID := cid.String() + "/" + treeID
 	s, ok := f.treeMap[fullID]
 	if !ok {

pkg/local_object_storage/pilorama/forest_test.go

@@ -4,6 +4,7 @@ import (
 	"math/rand"
 	"os"
 	"path/filepath"
+	"strconv"
 	"testing"
 
 	cidSDK "github.com/nspcc-dev/neofs-sdk-go/container/id"
@@ -206,6 +207,12 @@ func testForestTreeAddByPath(t *testing.T, s Forest) {
 	meta := []KeyValue{
 		{Key: AttributeVersion, Value: []byte("XXX")},
 		{Key: AttributeFilename, Value: []byte("file.txt")}}
+
+	t.Run("invalid attribute", func(t *testing.T) {
+		_, err := s.TreeAddByPath(cid, treeID, AttributeVersion, []string{"yyy"}, meta)
+		require.ErrorIs(t, err, ErrNotPathAttribute)
+	})
+
 	lm, err := s.TreeAddByPath(cid, treeID, AttributeFilename, []string{"path", "to"}, meta)
 	require.NoError(t, err)
 	require.Equal(t, 3, len(lm))
@@ -408,24 +415,33 @@ func testForestTreeApplyRandom(t *testing.T, constructor func(t testing.TB) Fore
 		ops[i] = Move{
 			Parent: 0,
 			Meta: Meta{
-				Time:  Timestamp(i),
+				Time: Timestamp(i),
-				Items: []KeyValue{{Value: make([]byte, 10)}},
+				Items: []KeyValue{
+					{Key: AttributeFilename, Value: []byte(strconv.Itoa(i))},
+					{Value: make([]byte, 10)},
+				},
 			},
 			Child: uint64(i) + 1,
 		}
-		rand.Read(ops[i].Meta.Items[0].Value)
+		rand.Read(ops[i].Meta.Items[1].Value)
 	}
 
 	for i := nodeCount; i < len(ops); i++ {
 		ops[i] = Move{
 			Parent: rand.Uint64() % (nodeCount + 1),
 			Meta: Meta{
-				Time:  Timestamp(i + nodeCount),
+				Time: Timestamp(i + nodeCount),
-				Items: []KeyValue{{Value: make([]byte, 10)}},
+				Items: []KeyValue{
+					{Key: AttributeFilename, Value: []byte(strconv.Itoa(i))},
+					{Value: make([]byte, 10)},
+				},
 			},
 			Child: rand.Uint64() % (nodeCount + 1),
 		}
-		rand.Read(ops[i].Meta.Items[0].Value)
+		if rand.Uint32()%5 == 0 {
+			ops[i].Parent = TrashID
+		}
+		rand.Read(ops[i].Meta.Items[1].Value)
 	}
 	for i := range ops {
 		require.NoError(t, expected.TreeApply(cid, treeID, &ops[i]))
@@ -558,6 +574,11 @@ func testTreeGetByPath(t *testing.T, s Forest) {
 		})
 	}
 
+	t.Run("invalid attribute", func(t *testing.T) {
+		_, err := s.TreeGetByPath(cid, treeID, AttributeVersion, []string{"", "TTT"}, false)
+		require.ErrorIs(t, err, ErrNotPathAttribute)
+	})
+
 	nodes, err := s.TreeGetByPath(cid, treeID, AttributeFilename, []string{"b", "cat1.jpg"}, false)
 	require.NoError(t, err)
 	require.Equal(t, []Node{4, 5}, nodes)

pkg/local_object_storage/pilorama/types.go

@@ -48,5 +48,16 @@ const (
 	TrashID = math.MaxUint64
 )
 
-// ErrTreeNotFound is returned when the requested tree is not found.
+var (
-var ErrTreeNotFound = errors.New("tree not found")
+	// ErrTreeNotFound is returned when the requested tree is not found.
+	ErrTreeNotFound = errors.New("tree not found")
+	// ErrNotPathAttribute is returned when the path is trying to be constructed with a non-internal
+	// attribute. Currently the only attribute allowed is AttributeFilename.
+	ErrNotPathAttribute = errors.New("attribute can't be used in path construction")
+)
+
+// isAttributeInternal returns true iff key can be used in `*ByPath` methods.
+// For such attributes an additional index is maintained in the database.
+func isAttributeInternal(key string) bool {
+	return key == AttributeFilename
+}