Add keyset pagination to find projects

* update housekeeping test not to set project id to zero value

server/backend/database/database.go

@@ -139,7 +139,7 @@ type Database interface {
 		ctx context.Context,
 		candidatesLimitPerProject int,
 		projectFetchSize int,
-		projectPage *int,
+		housekeepingLastProjectID *types.ID,
 	) ([]*ClientInfo, error)
 
 	// FindDocInfoByKey finds the document of the given key.

server/backend/database/memory/database.go

@@ -18,6 +18,7 @@
 package memory
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	gotime "time"
@@ -228,12 +229,11 @@ func (d *DB) CreateProjectInfo(
 func (d *DB) listProjectInfos(
 	ctx context.Context,
 	pageSize int,
-	page *int,
+	housekeepingLastProjectID *types.ID,
 ) ([]*database.ProjectInfo, error) {
 	txn := d.db.Txn(false)
 	defer txn.Abort()
 
-	offset := (*page) * pageSize
 	iter, err := txn.Get(
 		tblProjects,
 		"id",
@@ -242,23 +242,35 @@ func (d *DB) listProjectInfos(
 		return nil, fmt.Errorf("fetch all projects: %w", err)
 	}
 
-	var infos []*database.ProjectInfo
-
-	for i := 0; i < offset; i++ {
-		iter.Next()
+	lastIDBytes, err := housekeepingLastProjectID.Bytes()
+	if err != nil {
+		return nil, fmt.Errorf("decode last project id: %w", err)
 	}
 
-	for i := 0; i < pageSize; i++ {
+	var infos []*database.ProjectInfo
+	for i := 0; i < pageSize; {
 		raw := iter.Next()
 		if raw == nil {
-			*page = 0
+			*housekeepingLastProjectID = database.DefaultProjectID
 			break
 		}
+
 		info := raw.(*database.ProjectInfo).DeepCopy()
-		infos = append(infos, info)
-	}
 
-	*page++
+		idBytes, err := info.ID.Bytes()
+		if err != nil {
+			return nil, fmt.Errorf("decode project id: %w", err)
+		}
+
+		if bytes.Compare(idBytes, lastIDBytes) > 0 {
+			infos = append(infos, info)
+			i++
+		}
+
+		if i == pageSize {
+			*housekeepingLastProjectID = infos[len(infos)-1].ID
+		}
+	}
 	return infos, nil
 }
 
@@ -611,9 +623,9 @@ func (d *DB) FindDeactivateCandidates(
 	ctx context.Context,
 	candidatesLimitPerProject int,
 	projectFetchSize int,
-	projectPage *int,
+	housekeepingLastProjectID *types.ID,
 ) ([]*database.ClientInfo, error) {
-	projects, err := d.listProjectInfos(ctx, projectFetchSize, projectPage)
+	projects, err := d.listProjectInfos(ctx, projectFetchSize, housekeepingLastProjectID)
 	if err != nil {
 		return nil, err
 	}

server/backend/database/memory/housekeeping_test.go

@@ -28,6 +28,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	monkey "github.com/undefinedlabs/go-mpatch"
 
+	"github.com/yorkie-team/yorkie/server/backend/database"
 	"github.com/yorkie-team/yorkie/server/backend/database/memory"
 )
 
@@ -39,7 +40,10 @@ func TestHousekeeping(t *testing.T) {
 		ctx := context.Background()
 
 		clientDeactivateThreshold := "23h"
-		_, project, err := memdb.EnsureDefaultUserAndProject(ctx, "test", "test", clientDeactivateThreshold)
+
+		userInfo, err := memdb.CreateUserInfo(ctx, "test", "test")
+		assert.NoError(t, err)
+		project, err := memdb.CreateProjectInfo(ctx, database.DefaultProjectName, userInfo.ID, clientDeactivateThreshold)
 		assert.NoError(t, err)
 
 		yesterday := gotime.Now().Add(-24 * gotime.Hour)
@@ -59,12 +63,12 @@ func TestHousekeeping(t *testing.T) {
 		clientC, err := memdb.ActivateClient(ctx, project.ID, fmt.Sprintf("%s-C", t.Name()))
 		assert.NoError(t, err)
 
-		page := 0
+		housekeepingLastProjectID := database.DefaultProjectID
 		candidates, err := memdb.FindDeactivateCandidates(
 			ctx,
 			10,
 			10,
-			&page,
+			&housekeepingLastProjectID,
 		)
 		assert.NoError(t, err)
 		assert.Len(t, candidates, 2)

server/backend/database/mongo/client.go

@@ -239,13 +239,21 @@ func (c *Client) CreateProjectInfo(
 func (c *Client) listProjectInfos(
 	ctx context.Context,
 	pageSize int,
-	page *int,
+	housekeepingLastProjectID *types.ID,
 ) ([]*database.ProjectInfo, error) {
+	encodedID, err := encodeID(*housekeepingLastProjectID)
+	if err != nil {
+		return nil, err
+	}
+
 	opts := options.Find()
-	opts.SetSkip(int64((*page) * pageSize))
 	opts.SetLimit(int64(pageSize))
 
-	cursor, err := c.collection(colProjects).Find(ctx, bson.D{{}}, opts)
+	cursor, err := c.collection(colProjects).Find(ctx, bson.M{
+		"_id": bson.M{
+			"$gt": encodedID,
+		},
+	}, opts)
 	if err != nil {
 		return nil, fmt.Errorf("find project infos: %w", err)
 	}
@@ -255,12 +263,12 @@ func (c *Client) listProjectInfos(
 		return nil, fmt.Errorf("fetch project infos: %w", err)
 	}
 
-	isLastPage := len(infos) < pageSize
-	if isLastPage {
-		*page = 0
+	if len(infos) < pageSize {
+		*housekeepingLastProjectID = database.DefaultProjectID
+	} else if len(infos) > 0 {
+		*housekeepingLastProjectID = infos[len(infos)-1].ID
 	}
 
-	*page++
 	return infos, nil
 }
 
@@ -667,9 +675,9 @@ func (c *Client) FindDeactivateCandidates(
 	ctx context.Context,
 	candidatesLimitPerProject int,
 	projectFetchSize int,
-	projectPage *int,
+	housekeepingLastProjectID *types.ID,
 ) ([]*database.ClientInfo, error) {
-	projects, err := c.listProjectInfos(ctx, projectFetchSize, projectPage)
+	projects, err := c.listProjectInfos(ctx, projectFetchSize, housekeepingLastProjectID)
 	if err != nil {
 		return nil, err
 	}

server/backend/housekeeping/housekeeping.go

@@ -24,6 +24,7 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/yorkie-team/yorkie/api/types"
 	"github.com/yorkie-team/yorkie/server/backend/database"
 	"github.com/yorkie-team/yorkie/server/backend/sync"
 	"github.com/yorkie-team/yorkie/server/clients"
@@ -107,11 +108,11 @@ func (h *Housekeeping) Stop() error {
 
 // run is the housekeeping loop.
 func (h *Housekeeping) run() {
-	housekeepingProjectPage := 0
+	housekeepingLastProjectID := database.DefaultProjectID
 
 	for {
 		ctx := context.Background()
-		if err := h.deactivateCandidates(ctx, &housekeepingProjectPage); err != nil {
+		if err := h.deactivateCandidates(ctx, &housekeepingLastProjectID); err != nil {
 			continue
 		}
 
@@ -124,7 +125,7 @@ func (h *Housekeeping) run() {
 }
 
 // deactivateCandidates deactivates candidates.
-func (h *Housekeeping) deactivateCandidates(ctx context.Context, page *int) error {
+func (h *Housekeeping) deactivateCandidates(ctx context.Context, housekeepingLastProjectID *types.ID) error {
 	start := time.Now()
 	locker, err := h.coordinator.NewLocker(ctx, deactivateCandidatesKey)
 	if err != nil {
@@ -145,7 +146,7 @@ func (h *Housekeeping) deactivateCandidates(ctx context.Context, page *int) erro
 		ctx,
 		h.candidatesLimitPerProject,
 		h.projectFetchSize,
-		page,
+		housekeepingLastProjectID,
 	)
 	if err != nil {
 		return err

server/rpc/server_test.go

@@ -83,8 +83,9 @@ func TestMain(m *testing.M) {
 		ConnectionTimeout: helper.MongoConnectionTimeout,
 		PingTimeout:       helper.MongoPingTimeout,
 	}, &housekeeping.Config{
-		Interval:                  helper.HousekeepingInterval.String(),
-		CandidatesLimitPerProject: helper.HousekeepingCandidatesLimitPerProject,
+		Interval:                     helper.HousekeepingInterval.String(),
+		CandidatesLimitPerProject:    helper.HousekeepingCandidatesLimitPerProject,
+		HousekeepingProjectFetchSize: helper.HousekeepingProjectFetchSize,
 	}, met)
 	if err != nil {
 		log.Fatal(err)