[#81] node: Add basic read/write benchmarks for substorages

Signed-off-by: Alejandro Lopez <a.lopez@yadro.com>

go.mod

@@ -39,6 +39,8 @@ require (
 	gopkg.in/yaml.v3 v3.0.1
 )
 
+require golang.org/x/exp v0.0.0-20230224173230-c95f2b4c22f2
+
 require (
 	git.frostfs.info/TrueCloudLab/frostfs-crypto v0.6.0 // indirect
 	git.frostfs.info/TrueCloudLab/rfc6979 v0.4.0 // indirect
@@ -91,7 +93,6 @@ require (
 	github.com/urfave/cli v1.22.5 // indirect
 	go.uber.org/multierr v1.9.0 // indirect
 	golang.org/x/crypto v0.4.0 // indirect
-	golang.org/x/exp v0.0.0-20221227203929-1b447090c38c // indirect
 	golang.org/x/net v0.4.0 // indirect
 	golang.org/x/sync v0.1.0 // indirect
 	golang.org/x/sys v0.3.0 // indirect

go.sum

@@ -545,8 +545,8 @@ golang.org/x/exp v0.0.0-20191227195350-da58074b4299/go.mod h1:2RIsYlXP63K8oxa1u0
 golang.org/x/exp v0.0.0-20200119233911-0405dc783f0a/go.mod h1:2RIsYlXP63K8oxa1u096TMicItID8zy7Y6sNkU49FU4=
 golang.org/x/exp v0.0.0-20200207192155-f17229e696bd/go.mod h1:J/WKrq2StrnmMY6+EHIKF9dgMWnmCNThgcyBT1FY9mM=
 golang.org/x/exp v0.0.0-20200224162631-6cc2880d07d6/go.mod h1:3jZMyOhIsHpP37uCMkUooju7aAi5cS1Q23tOzKc+0MU=
-golang.org/x/exp v0.0.0-20221227203929-1b447090c38c h1:Govq2W3bnHJimHT2ium65kXcI7ZzTniZHcFATnLJM0Q=
+golang.org/x/exp v0.0.0-20230224173230-c95f2b4c22f2 h1:Jvc7gsqn21cJHCmAWx0LiimpP18LZmUxkT5Mp7EZ1mI=
-golang.org/x/exp v0.0.0-20221227203929-1b447090c38c/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
+golang.org/x/exp v0.0.0-20230224173230-c95f2b4c22f2/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
 golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
 golang.org/x/image v0.0.0-20190802002840-cff245a6509b/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=

pkg/local_object_storage/blobstor/memstore/control.go

@@ -0,0 +1,15 @@
+package memstore
+
+import "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/compression"
+
+func (s *memstoreImpl) Open(readOnly bool) error {
+	s.readOnly = readOnly
+	return nil
+}
+
+func (s *memstoreImpl) Init() error                              { return nil }
+func (s *memstoreImpl) Close() error                             { return nil }
+func (s *memstoreImpl) Type() string                             { return Type }
+func (s *memstoreImpl) Path() string                             { return s.rootPath }
+func (s *memstoreImpl) SetCompressor(cc *compression.Config)     { s.compression = cc }
+func (s *memstoreImpl) SetReportErrorFunc(f func(string, error)) { s.reportError = f }

pkg/local_object_storage/blobstor/memstore/memstore.go

@@ -0,0 +1,168 @@
+// Package memstore implements a memory-backed common.Storage for testing purposes.
+package memstore
+
+import (
+	"fmt"
+	"sync"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/common"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/util/logicerr"
+	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+)
+
+const Type = "memstore"
+
+type memstoreImpl struct {
+	*cfg
+	mu   sync.RWMutex
+	objs map[string][]byte
+}
+
+func New(opts ...Option) common.Storage {
+	st := &memstoreImpl{
+		cfg:  defaultConfig(),
+		objs: map[string][]byte{},
+	}
+
+	for _, opt := range opts {
+		opt(st.cfg)
+	}
+
+	return st
+}
+
+func (s *memstoreImpl) Get(req common.GetPrm) (common.GetRes, error) {
+	key := req.Address.EncodeToString()
+
+	s.mu.RLock()
+	data, exists := s.objs[key]
+	s.mu.RUnlock()
+
+	if !exists {
+		return common.GetRes{}, logicerr.Wrap(apistatus.ObjectNotFound{})
+	}
+
+	// Decompress the data.
+	var err error
+	if data, err = s.compression.Decompress(data); err != nil {
+		return common.GetRes{}, fmt.Errorf("could not decompress object data: %w", err)
+	}
+
+	// Unmarshal the SDK object.
+	obj := objectSDK.New()
+	if err := obj.Unmarshal(data); err != nil {
+		return common.GetRes{}, fmt.Errorf("could not unmarshal the object: %w", err)
+	}
+
+	return common.GetRes{Object: obj, RawData: data}, nil
+}
+
+func (s *memstoreImpl) GetRange(req common.GetRangePrm) (common.GetRangeRes, error) {
+	getResp, err := s.Get(common.GetPrm{
+		Address:   req.Address,
+		StorageID: req.StorageID,
+	})
+	if err != nil {
+		return common.GetRangeRes{}, err
+	}
+
+	payload := getResp.Object.Payload()
+	from := req.Range.GetOffset()
+	to := from + req.Range.GetLength()
+
+	if pLen := uint64(len(payload)); to < from || pLen < from || pLen < to {
+		return common.GetRangeRes{}, logicerr.Wrap(apistatus.ObjectOutOfRange{})
+	}
+
+	return common.GetRangeRes{
+		Data: payload[from:to],
+	}, nil
+}
+
+func (s *memstoreImpl) Exists(req common.ExistsPrm) (common.ExistsRes, error) {
+	key := req.Address.EncodeToString()
+
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	_, exists := s.objs[key]
+	return common.ExistsRes{Exists: exists}, nil
+
+}
+
+func (s *memstoreImpl) Put(req common.PutPrm) (common.PutRes, error) {
+	if s.readOnly {
+		return common.PutRes{}, common.ErrReadOnly
+	}
+	if !req.DontCompress {
+		req.RawData = s.compression.Compress(req.RawData)
+	}
+
+	key := req.Address.EncodeToString()
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	s.objs[key] = req.RawData
+	return common.PutRes{StorageID: []byte(s.rootPath)}, nil
+}
+
+func (s *memstoreImpl) Delete(req common.DeletePrm) (common.DeleteRes, error) {
+	if s.readOnly {
+		return common.DeleteRes{}, common.ErrReadOnly
+	}
+
+	key := req.Address.EncodeToString()
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if _, exists := s.objs[key]; exists {
+		delete(s.objs, key)
+		return common.DeleteRes{}, nil
+	}
+
+	return common.DeleteRes{}, logicerr.Wrap(apistatus.ObjectNotFound{})
+}
+
+func (s *memstoreImpl) Iterate(req common.IteratePrm) (common.IterateRes, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	for k, v := range s.objs {
+		elem := common.IterationElement{
+			ObjectData: v,
+		}
+		if err := elem.Address.DecodeString(string(k)); err != nil {
+			if req.IgnoreErrors {
+				continue
+			}
+			return common.IterateRes{}, logicerr.Wrap(fmt.Errorf("(%T) decoding address string %q: %v", s, string(k), err))
+		}
+		var err error
+		if elem.ObjectData, err = s.compression.Decompress(elem.ObjectData); err != nil {
+			if req.IgnoreErrors {
+				if req.ErrorHandler != nil {
+					return common.IterateRes{}, req.ErrorHandler(elem.Address, err)
+				}
+				continue
+			}
+			return common.IterateRes{}, logicerr.Wrap(fmt.Errorf("(%T) decompressing data for address %q: %v", s, elem.Address.String(), err))
+		}
+		switch {
+		case req.Handler != nil:
+			if err := req.Handler(elem); err != nil {
+				return common.IterateRes{}, err
+			}
+		case req.LazyHandler != nil:
+			if err := req.LazyHandler(elem.Address, func() ([]byte, error) { return elem.ObjectData, nil }); err != nil {
+				return common.IterateRes{}, err
+			}
+		default:
+			if !req.IgnoreErrors {
+				return common.IterateRes{}, logicerr.Wrap(fmt.Errorf("(%T) no Handler or LazyHandler set for IteratePrm", s))
+			}
+		}
+	}
+	return common.IterateRes{}, nil
+}

pkg/local_object_storage/blobstor/memstore/memstore_test.go

@@ -0,0 +1,68 @@
+package memstore
+
+import (
+	"testing"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/object"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/common"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/internal/blobstortest"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger"
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/zap/zaptest"
+)
+
+func TestSimpleLifecycle(t *testing.T) {
+	s := New(
+		WithRootPath("memstore"),
+		WithLogger(&logger.Logger{Logger: zaptest.NewLogger(t)}),
+	)
+	t.Cleanup(func() { _ = s.Close() })
+	require.NoError(t, s.Open(false))
+	require.NoError(t, s.Init())
+
+	obj := blobstortest.NewObject(1024)
+	addr := object.AddressOf(obj)
+	d, err := obj.Marshal()
+	require.NoError(t, err)
+
+	{
+		_, err := s.Put(common.PutPrm{Address: addr, RawData: d, DontCompress: true})
+		require.NoError(t, err)
+	}
+
+	{
+		resp, err := s.Exists(common.ExistsPrm{Address: addr})
+		require.NoError(t, err)
+		require.True(t, resp.Exists)
+	}
+
+	{
+		resp, err := s.Get(common.GetPrm{Address: addr})
+		require.NoError(t, err)
+		require.Equal(t, obj.Payload(), resp.Object.Payload())
+	}
+
+	{
+		var objRange objectSDK.Range
+		objRange.SetOffset(256)
+		objRange.SetLength(512)
+		resp, err := s.GetRange(common.GetRangePrm{
+			Address: addr,
+			Range:   objRange,
+		})
+		require.NoError(t, err)
+		require.Equal(t, obj.Payload()[objRange.GetOffset():objRange.GetOffset()+objRange.GetLength()], resp.Data)
+	}
+
+	{
+		_, err := s.Delete(common.DeletePrm{Address: addr})
+		require.NoError(t, err)
+	}
+
+	{
+		resp, err := s.Exists(common.ExistsPrm{Address: addr})
+		require.NoError(t, err)
+		require.False(t, resp.Exists)
+	}
+}

pkg/local_object_storage/blobstor/memstore/option.go

@@ -0,0 +1,42 @@
+package memstore
+
+import (
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/compression"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger"
+	"go.uber.org/zap"
+)
+
+type cfg struct {
+	log         *logger.Logger
+	rootPath    string
+	readOnly    bool
+	compression *compression.Config
+	reportError func(string, error)
+}
+
+func defaultConfig() *cfg {
+	return &cfg{
+		log:         &logger.Logger{Logger: zap.L()},
+		reportError: func(string, error) {},
+	}
+}
+
+type Option func(*cfg)
+
+func WithLogger(l *logger.Logger) Option {
+	return func(c *cfg) {
+		c.log = l
+	}
+}
+
+func WithRootPath(p string) Option {
+	return func(c *cfg) {
+		c.rootPath = p
+	}
+}
+
+func WithReadOnly(ro bool) Option {
+	return func(c *cfg) {
+		c.readOnly = ro
+	}
+}

pkg/local_object_storage/blobstor/perf_test.go

@@ -0,0 +1,402 @@
+package blobstor
+
+import (
+	"encoding/binary"
+	"fmt"
+	"os"
+	"testing"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/blobovniczatree"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/common"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/fstree"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/memstore"
+	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
+	cidtest "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id/test"
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
+	oidtest "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id/test"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/atomic"
+	"golang.org/x/exp/rand"
+	"golang.org/x/exp/slices"
+)
+
+// The storages to benchmark. Each storage has a description and a function which returns the actual
+// storage along with a cleanup function.
+var storages = []struct {
+	desc   string
+	create func(*testing.B) (common.Storage, func())
+}{
+	{
+		desc: "memstore",
+		create: func(*testing.B) (common.Storage, func()) {
+			return memstore.New(), func() {}
+		},
+	},
+	{
+		desc: "fstree_nosync",
+		create: func(b *testing.B) (common.Storage, func()) {
+			dir, err := os.MkdirTemp(os.TempDir(), "fstree_nosync")
+			if err != nil {
+				b.Fatalf("creating fstree_nosync root path: %v", err)
+			}
+			cleanup := func() { os.RemoveAll(dir) }
+			return fstree.New(
+				fstree.WithPath(dir),
+				fstree.WithDepth(2),
+				fstree.WithDirNameLen(2),
+				fstree.WithNoSync(true),
+			), cleanup
+		},
+	},
+	{
+		desc: "fstree",
+		create: func(b *testing.B) (common.Storage, func()) {
+			dir, err := os.MkdirTemp(os.TempDir(), "fstree")
+			if err != nil {
+				b.Fatalf("creating fstree root path: %v", err)
+			}
+			cleanup := func() { os.RemoveAll(dir) }
+			return fstree.New(
+				fstree.WithPath(dir),
+				fstree.WithDepth(2),
+				fstree.WithDirNameLen(2),
+			), cleanup
+		},
+	},
+	{
+		desc: "blobovniczatree",
+		create: func(b *testing.B) (common.Storage, func()) {
+			dir, err := os.MkdirTemp(os.TempDir(), "blobovniczatree")
+			if err != nil {
+				b.Fatalf("creating blobovniczatree root path: %v", err)
+			}
+			cleanup := func() { os.RemoveAll(dir) }
+			return blobovniczatree.NewBlobovniczaTree(
+				blobovniczatree.WithRootPath(dir),
+			), cleanup
+		},
+	},
+}
+
+func BenchmarkSubstorageReadPerf(b *testing.B) {
+	readTests := []struct {
+		desc    string
+		size    int
+		objGen  func() objectGenerator
+		addrGen func() addressGenerator
+	}{
+		{
+			desc:    "seq100",
+			size:    10000,
+			objGen:  func() objectGenerator { return &seqObjGenerator{objSize: 100} },
+			addrGen: func() addressGenerator { return &seqAddrGenerator{maxID: 100} },
+		},
+		{
+			desc:    "rand100",
+			size:    10000,
+			objGen:  func() objectGenerator { return &seqObjGenerator{objSize: 100} },
+			addrGen: func() addressGenerator { return randAddrGenerator(10000) },
+		},
+	}
+	for _, tt := range readTests {
+		for _, stEntry := range storages {
+			b.Run(fmt.Sprintf("%s-%s", stEntry.desc, tt.desc), func(b *testing.B) {
+				objGen := tt.objGen()
+				st, cleanup := stEntry.create(b)
+
+				require.NoError(b, st.Open(false))
+				require.NoError(b, st.Init())
+
+				// Fill database
+				for i := 0; i < tt.size; i++ {
+					obj := objGen.Next()
+					addr := addressFromObject(obj)
+					raw, err := obj.Marshal()
+					require.NoError(b, err)
+					if _, err := st.Put(common.PutPrm{
+						Address: addr,
+						RawData: raw,
+					}); err != nil {
+						b.Fatalf("writing entry: %v", err)
+					}
+				}
+
+				// Benchmark reading
+				addrGen := tt.addrGen()
+				b.ResetTimer()
+				b.RunParallel(func(pb *testing.PB) {
+					for pb.Next() {
+						_, err := st.Get(common.GetPrm{Address: addrGen.Next()})
+						require.NoError(b, err)
+					}
+				})
+
+				require.NoError(b, st.Close())
+				cleanup()
+			})
+		}
+	}
+}
+
+func BenchmarkSubstorageWritePerf(b *testing.B) {
+	generators := []struct {
+		desc   string
+		create func() objectGenerator
+	}{
+		{desc: "rand10", create: func() objectGenerator { return &randObjGenerator{objSize: 10} }},
+		{desc: "rand100", create: func() objectGenerator { return &randObjGenerator{objSize: 100} }},
+		{desc: "rand1000", create: func() objectGenerator { return &randObjGenerator{objSize: 1000} }},
+		{desc: "overwrite10", create: func() objectGenerator { return &overwriteObjGenerator{objSize: 10, maxObjects: 100} }},
+		{desc: "overwrite100", create: func() objectGenerator { return &overwriteObjGenerator{objSize: 100, maxObjects: 100} }},
+		{desc: "overwrite1000", create: func() objectGenerator { return &overwriteObjGenerator{objSize: 1000, maxObjects: 100} }},
+	}
+
+	for _, genEntry := range generators {
+		for _, stEntry := range storages {
+			b.Run(fmt.Sprintf("%s-%s", stEntry.desc, genEntry.desc), func(b *testing.B) {
+				gen := genEntry.create()
+				st, cleanup := stEntry.create(b)
+
+				require.NoError(b, st.Open(false))
+				require.NoError(b, st.Init())
+
+				b.ResetTimer()
+				b.RunParallel(func(pb *testing.PB) {
+					for pb.Next() {
+						obj := gen.Next()
+						addr := addressFromObject(obj)
+						raw, err := obj.Marshal()
+						require.NoError(b, err)
+						if _, err := st.Put(common.PutPrm{
+							Address: addr,
+							RawData: raw,
+						}); err != nil {
+							b.Fatalf("writing entry: %v", err)
+						}
+					}
+				})
+
+				require.NoError(b, st.Close())
+				cleanup()
+			})
+		}
+	}
+}
+
+func BenchmarkSubstorageIteratePerf(b *testing.B) {
+	iterateTests := []struct {
+		desc   string
+		size   int
+		objGen func() objectGenerator
+	}{
+		{
+			desc:   "rand100",
+			size:   10000,
+			objGen: func() objectGenerator { return &randObjGenerator{objSize: 100} },
+		},
+	}
+	for _, tt := range iterateTests {
+		for _, stEntry := range storages {
+			b.Run(fmt.Sprintf("%s-%s", stEntry.desc, tt.desc), func(b *testing.B) {
+				objGen := tt.objGen()
+				st, cleanup := stEntry.create(b)
+
+				require.NoError(b, st.Open(false))
+				require.NoError(b, st.Init())
+
+				// Fill database
+				for i := 0; i < tt.size; i++ {
+					obj := objGen.Next()
+					addr := addressFromObject(obj)
+					raw, err := obj.Marshal()
+					require.NoError(b, err)
+					if _, err := st.Put(common.PutPrm{
+						Address: addr,
+						RawData: raw,
+					}); err != nil {
+						b.Fatalf("writing entry: %v", err)
+					}
+				}
+
+				// Benchmark iterate
+				cnt := 0
+				b.ResetTimer()
+				_, err := st.Iterate(common.IteratePrm{
+					Handler: func(elem common.IterationElement) error {
+						cnt++
+						return nil
+					},
+				})
+				require.NoError(b, err)
+				require.Equal(b, tt.size, cnt)
+				b.StopTimer()
+
+				require.NoError(b, st.Close())
+				cleanup()
+			})
+		}
+	}
+}
+
+func addressFromObject(obj *objectSDK.Object) oid.Address {
+	var addr oid.Address
+	if id, isSet := obj.ID(); isSet {
+		addr.SetObject(id)
+	} else {
+		panic("object ID is not set")
+	}
+	if cid, isSet := obj.ContainerID(); isSet {
+		addr.SetContainer(cid)
+	} else {
+		panic("container ID is not set")
+	}
+	return addr
+}
+
+// addressGenerator is the interface of types that generate object addresses.
+type addressGenerator interface {
+	Next() oid.Address
+}
+
+// seqAddrGenerator is an addressGenerator that generates addresses sequentially and wraps around the given max ID.
+type seqAddrGenerator struct {
+	cnt   atomic.Uint64
+	maxID uint64
+}
+
+func (g *seqAddrGenerator) Next() oid.Address {
+	var id oid.ID
+	binary.LittleEndian.PutUint64(id[:], ((g.cnt.Inc()-1)%g.maxID)+1)
+	var addr oid.Address
+	addr.SetContainer(cid.ID{})
+	addr.SetObject(id)
+	return addr
+}
+
+func TestSeqAddrGenerator(t *testing.T) {
+	gen := &seqAddrGenerator{maxID: 10}
+	for i := 1; i <= 20; i++ {
+		addr := gen.Next()
+		id := addr.Object()
+
+		require.Equal(t, uint64((i-1)%int(gen.maxID)+1), binary.LittleEndian.Uint64(id[:]))
+	}
+}
+
+// randAddrGenerator is an addressGenerator that generates random addresses in the given range.
+type randAddrGenerator uint64
+
+func (g randAddrGenerator) Next() oid.Address {
+	var id oid.ID
+	binary.LittleEndian.PutUint64(id[:], uint64(1+int(rand.Int63n(int64(g)))))
+	var addr oid.Address
+	addr.SetContainer(cid.ID{})
+	addr.SetObject(id)
+	return addr
+}
+
+func TestRandAddrGenerator(t *testing.T) {
+	gen := randAddrGenerator(5)
+	for i := 0; i < 50; i++ {
+		addr := gen.Next()
+		id := addr.Object()
+		k := binary.LittleEndian.Uint64(id[:])
+
+		require.True(t, 1 <= k && k <= uint64(gen))
+	}
+}
+
+// objectGenerator is the interface of types that generate object entries.
+type objectGenerator interface {
+	Next() *objectSDK.Object
+}
+
+// seqObjGenerator is an objectGenerator that generates entries with random payloads of size objSize and sequential IDs.
+type seqObjGenerator struct {
+	cnt     atomic.Uint64
+	objSize uint64
+}
+
+func (g *seqObjGenerator) Next() *objectSDK.Object {
+	var id oid.ID
+	binary.LittleEndian.PutUint64(id[:], g.cnt.Inc())
+	return genObject(id, cid.ID{}, g.objSize)
+}
+
+func TestSeqObjGenerator(t *testing.T) {
+	gen := &seqObjGenerator{objSize: 10}
+	var addrs []string
+	for i := 1; i <= 10; i++ {
+		obj := gen.Next()
+		id, isSet := obj.ID()
+		addrs = append(addrs, addressFromObject(obj).EncodeToString())
+
+		require.True(t, isSet)
+		require.Equal(t, gen.objSize, uint64(len(obj.Payload())))
+		require.Equal(t, uint64(i), binary.LittleEndian.Uint64(id[:]))
+	}
+	require.True(t, slices.IsSorted(addrs))
+}
+
+// randObjGenerator is an objectGenerator that generates entries with random IDs and payloads of size objSize.
+type randObjGenerator struct {
+	objSize uint64
+}
+
+func (g *randObjGenerator) Next() *objectSDK.Object {
+	return genObject(oidtest.ID(), cidtest.ID(), g.objSize)
+}
+
+func TestRandObjGenerator(t *testing.T) {
+	gen := &randObjGenerator{objSize: 10}
+	for i := 0; i < 10; i++ {
+		obj := gen.Next()
+
+		require.Equal(t, gen.objSize, uint64(len(obj.Payload())))
+	}
+}
+
+// overwriteObjGenerator is an objectGenerator that generates entries with random payloads of size objSize and at most maxObjects distinct IDs.
+type overwriteObjGenerator struct {
+	objSize    uint64
+	maxObjects uint64
+}
+
+func (g *overwriteObjGenerator) Next() *objectSDK.Object {
+	var id oid.ID
+	binary.LittleEndian.PutUint64(id[:], uint64(1+rand.Int63n(int64(g.maxObjects))))
+	return genObject(id, cid.ID{}, g.objSize)
+}
+
+func TestOverwriteObjGenerator(t *testing.T) {
+	gen := &overwriteObjGenerator{
+		objSize:    10,
+		maxObjects: 4,
+	}
+	for i := 0; i < 40; i++ {
+		obj := gen.Next()
+		id, isSet := obj.ID()
+		i := binary.LittleEndian.Uint64(id[:])
+
+		require.True(t, isSet)
+		require.Equal(t, gen.objSize, uint64(len(obj.Payload())))
+		require.True(t, 1 <= i && i <= gen.maxObjects)
+	}
+}
+
+// Generates an object with random payload and the given address and size.
+// TODO(#86): there's some testing-related dupes in many places. Probably worth
+// spending some time cleaning up a bit.
+func genObject(id oid.ID, cid cid.ID, sz uint64) *objectSDK.Object {
+	raw := objectSDK.New()
+
+	raw.SetID(id)
+	raw.SetContainerID(cid)
+
+	payload := make([]byte, sz)
+	rand.Read(payload)
+	raw.SetPayload(payload)
+
+	return raw
+}