enhance: Add PrimaryKeys interface to reduce memory usage (#30405)

See also #30404

`PrimaryKey` is used to hold pk values for both int64 & varchar data
type. Since it is an interface it may occupies more memory than pure
slices when holding a group of pks.

This PR add `PrimaryKeys` interface when some other module need to hold
lots of PrimaryKeys.
By using this interface, it could reduce the memory of pk slice to half
when using Int64 Pk data type and reduce interface cost for each row of
varchar as well.

---------

Signed-off-by: Congqi Xia <[email protected]>

internal/storage/primary_keys.go

@@ -0,0 +1,158 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package storage
+
+import (
+	"github.com/samber/lo"
+
+	"github.com/milvus-io/milvus-proto/go-api/v2/schemapb"
+	"github.com/milvus-io/milvus/pkg/util/merr"
+)
+
+// PrimaryKeys is the interface holding a slice of PrimaryKey
+type PrimaryKeys interface {
+	Append(pks ...PrimaryKey) error
+	MustAppend(pks ...PrimaryKey)
+	Get(idx int) PrimaryKey
+	Type() schemapb.DataType
+	Size() int64
+	Len() int
+	MustMerge(pks PrimaryKeys)
+}
+
+type Int64PrimaryKeys struct {
+	values []int64
+}
+
+func NewInt64PrimaryKeys(cap int) *Int64PrimaryKeys {
+	return &Int64PrimaryKeys{values: make([]int64, 0, cap)}
+}
+
+func (pks *Int64PrimaryKeys) AppendRaw(values ...int64) {
+	pks.values = append(pks.values, values...)
+}
+
+func (pks *Int64PrimaryKeys) Append(values ...PrimaryKey) error {
+	iValues := make([]int64, 0, len(values))
+	for _, pk := range values {
+		iPk, ok := pk.(*Int64PrimaryKey)
+		if !ok {
+			return merr.WrapErrParameterInvalid("Int64PrimaryKey", "non-int64 pk")
+		}
+		iValues = append(iValues, iPk.Value)
+	}
+
+	pks.AppendRaw(iValues...)
+	return nil
+}
+
+func (pks *Int64PrimaryKeys) MustAppend(values ...PrimaryKey) {
+	err := pks.Append(values...)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func (pks *Int64PrimaryKeys) Get(idx int) PrimaryKey {
+	return NewInt64PrimaryKey(pks.values[idx])
+}
+
+func (pks *Int64PrimaryKeys) Type() schemapb.DataType {
+	return schemapb.DataType_Int64
+}
+
+func (pks *Int64PrimaryKeys) Len() int {
+	return len(pks.values)
+}
+
+func (pks *Int64PrimaryKeys) Size() int64 {
+	return int64(pks.Len()) * 8
+}
+
+func (pks *Int64PrimaryKeys) MustMerge(another PrimaryKeys) {
+	aPks, ok := another.(*Int64PrimaryKeys)
+	if !ok {
+		panic("cannot merge different kind of pks")
+	}
+
+	pks.values = append(pks.values, aPks.values...)
+}
+
+type VarcharPrimaryKeys struct {
+	values []string
+	size   int64
+}
+
+func NewVarcharPrimaryKeys(cap int) *VarcharPrimaryKeys {
+	return &VarcharPrimaryKeys{
+		values: make([]string, 0, cap),
+	}
+}
+
+func (pks *VarcharPrimaryKeys) AppendRaw(values ...string) {
+	pks.values = append(pks.values, values...)
+	lo.ForEach(values, func(str string, _ int) {
+		pks.size += int64(len(str)) + 16
+	})
+}
+
+func (pks *VarcharPrimaryKeys) Append(values ...PrimaryKey) error {
+	sValues := make([]string, 0, len(values))
+	for _, pk := range values {
+		iPk, ok := pk.(*VarCharPrimaryKey)
+		if !ok {
+			return merr.WrapErrParameterInvalid("Int64PrimaryKey", "non-int64 pk")
+		}
+		sValues = append(sValues, iPk.Value)
+	}
+
+	pks.AppendRaw(sValues...)
+	return nil
+}
+
+func (pks *VarcharPrimaryKeys) MustAppend(values ...PrimaryKey) {
+	err := pks.Append(values...)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func (pks *VarcharPrimaryKeys) Get(idx int) PrimaryKey {
+	return NewVarCharPrimaryKey(pks.values[idx])
+}
+
+func (pks *VarcharPrimaryKeys) Type() schemapb.DataType {
+	return schemapb.DataType_VarChar
+}
+
+func (pks *VarcharPrimaryKeys) Len() int {
+	return len(pks.values)
+}
+
+func (pks *VarcharPrimaryKeys) Size() int64 {
+	return pks.size
+}
+
+func (pks *VarcharPrimaryKeys) MustMerge(another PrimaryKeys) {
+	aPks, ok := another.(*VarcharPrimaryKeys)
+	if !ok {
+		panic("cannot merge different kind of pks")
+	}
+
+	pks.values = append(pks.values, aPks.values...)
+	pks.size += aPks.size
+}

internal/storage/primary_keys_test.go

@@ -0,0 +1,137 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package storage
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+
+	"github.com/milvus-io/milvus-proto/go-api/v2/schemapb"
+)
+
+type PrimaryKeysSuite struct {
+	suite.Suite
+}
+
+func (s *PrimaryKeysSuite) TestAppend() {
+	s.Run("IntAppend", func() {
+		intPks := NewInt64PrimaryKeys(10)
+		s.Equal(schemapb.DataType_Int64, intPks.Type())
+		s.EqualValues(0, intPks.Len())
+		s.EqualValues(0, intPks.Size())
+
+		err := intPks.Append(NewInt64PrimaryKey(1))
+		s.NoError(err)
+		s.EqualValues(1, intPks.Len())
+		s.EqualValues(8, intPks.Size())
+
+		val := intPks.Get(0)
+		pk, ok := val.(*Int64PrimaryKey)
+		s.Require().True(ok)
+		s.EqualValues(1, pk.Value)
+
+		err = intPks.Append(NewVarCharPrimaryKey("1"))
+		s.Error(err)
+	})
+
+	s.Run("VarcharAppend", func() {
+		strPks := NewVarcharPrimaryKeys(10)
+		s.Equal(schemapb.DataType_VarChar, strPks.Type())
+		s.EqualValues(0, strPks.Len())
+		s.EqualValues(0, strPks.Size())
+
+		err := strPks.Append(NewVarCharPrimaryKey("1"))
+		s.NoError(err)
+		s.EqualValues(1, strPks.Len())
+		s.EqualValues(17, strPks.Size())
+		val := strPks.Get(0)
+		pk, ok := val.(*VarCharPrimaryKey)
+		s.Require().True(ok)
+		s.EqualValues("1", pk.Value)
+
+		err = strPks.Append(NewInt64PrimaryKey(1))
+		s.Error(err)
+	})
+
+	s.Run("IntMustAppend", func() {
+		intPks := NewInt64PrimaryKeys(10)
+
+		s.NotPanics(func() {
+			intPks.MustAppend(NewInt64PrimaryKey(1))
+		})
+		s.Panics(func() {
+			intPks.MustAppend(NewVarCharPrimaryKey("1"))
+		})
+	})
+
+	s.Run("VarcharMustAppend", func() {
+		strPks := NewVarcharPrimaryKeys(10)
+
+		s.NotPanics(func() {
+			strPks.MustAppend(NewVarCharPrimaryKey("1"))
+		})
+		s.Panics(func() {
+			strPks.MustAppend(NewInt64PrimaryKey(1))
+		})
+	})
+}
+
+func (s *PrimaryKeysSuite) TestMustMerge() {
+	s.Run("IntPksMustMerge", func() {
+		intPks := NewInt64PrimaryKeys(10)
+		intPks.AppendRaw(1, 2, 3)
+
+		anotherPks := NewInt64PrimaryKeys(10)
+		anotherPks.AppendRaw(4, 5, 6)
+
+		strPks := NewVarcharPrimaryKeys(10)
+		strPks.AppendRaw("1", "2", "3")
+
+		s.NotPanics(func() {
+			intPks.MustMerge(anotherPks)
+
+			s.Equal(6, intPks.Len())
+		})
+
+		s.Panics(func() {
+			intPks.MustMerge(strPks)
+		})
+	})
+
+	s.Run("StrPksMustMerge", func() {
+		strPks := NewVarcharPrimaryKeys(10)
+		strPks.AppendRaw("1", "2", "3")
+		intPks := NewInt64PrimaryKeys(10)
+		intPks.AppendRaw(1, 2, 3)
+		anotherPks := NewVarcharPrimaryKeys(10)
+		anotherPks.AppendRaw("4", "5", "6")
+
+		s.NotPanics(func() {
+			strPks.MustMerge(anotherPks)
+			s.Equal(6, strPks.Len())
+		})
+
+		s.Panics(func() {
+			strPks.MustMerge(intPks)
+		})
+	})
+}
+
+func TestPrimaryKeys(t *testing.T) {
+	suite.Run(t, new(PrimaryKeysSuite))
+}