diff --git a/database.go b/database.go
index 29b4fbb..36c6834 100644
--- a/database.go
+++ b/database.go
@@ -176,14 +176,14 @@ func (d *DB) GetBooks(query bson.M, r ...int) (books []Book, num int, err error)
 
 /* Get the most visited books
  */
-func (d *DB) GetVisitedBooks(num int) (books []Book, err error) {
+func (d *DB) GetVisitedBooks() (books []Book, err error) {
 	visitedColl := d.session.DB(DB_NAME).C(VISITED_COLL)
-	bookId, err := GetBooksVisited(num, visitedColl)
+	bookId, err := GetBooksVisited(visitedColl)
 	if err != nil {
 		return nil, err
 	}
 
-	books = make([]Book, num)
+	books = make([]Book, len(bookId))
 	for i, id := range bookId {
 		booksColl := d.session.DB(DB_NAME).C(BOOKS_COLL)
 		booksColl.Find(bson.M{"_id": id}).One(&books[i])
@@ -193,21 +193,22 @@ func (d *DB) GetVisitedBooks(num int) (books []Book, err error) {
 }
 
 func (d *DB) UpdateMostVisited() error {
-	statsColl := d.session.DB(DB_NAME).C(STATS_COLL)
-	mr := NewMR(d.session.DB(DB_NAME))
-	return mr.UpdateMostVisited(statsColl)
+	var u DBUpdate
+	u.src = d.session.DB(DB_NAME).C(STATS_COLL)
+	u.dst = d.session.DB(DB_NAME).C(VISITED_COLL)
+	return u.UpdateMostBooks("book")
 }
 
 /* Get the most downloaded books
  */
-func (d *DB) GetDownloadedBooks(num int) (books []Book, err error) {
+func (d *DB) GetDownloadedBooks() (books []Book, err error) {
 	downloadedColl := d.session.DB(DB_NAME).C(DOWNLOADED_COLL)
-	bookId, err := GetBooksVisited(num, downloadedColl)
+	bookId, err := GetBooksVisited(downloadedColl)
 	if err != nil {
 		return nil, err
 	}
 
-	books = make([]Book, num)
+	books = make([]Book, len(bookId))
 	for i, id := range bookId {
 		booksColl := d.session.DB(DB_NAME).C(BOOKS_COLL)
 		booksColl.Find(bson.M{"_id": id}).One(&books[i])
@@ -217,9 +218,10 @@ func (d *DB) GetDownloadedBooks(num int) (books []Book, err error) {
 }
 
 func (d *DB) UpdateDownloadedBooks() error {
-	statsColl := d.session.DB(DB_NAME).C(STATS_COLL)
-	mr := NewMR(d.session.DB(DB_NAME))
-	return mr.UpdateMostDownloaded(statsColl)
+	var u DBUpdate
+	u.src = d.session.DB(DB_NAME).C(STATS_COLL)
+	u.dst = d.session.DB(DB_NAME).C(DOWNLOADED_COLL)
+	return u.UpdateMostBooks("download")
 }
 
 /* optional parameters: length and start index
@@ -244,15 +246,16 @@ func (d *DB) GetFS(prefix string) *mgo.GridFS {
 	return d.session.DB(DB_NAME).GridFS(prefix)
 }
 
-func (d *DB) GetTags(numTags int) ([]string, error) {
+func (d *DB) GetTags() ([]string, error) {
 	tagsColl := d.session.DB(DB_NAME).C(TAGS_COLL)
-	return GetTags(numTags, tagsColl)
+	return GetTags(tagsColl)
 }
 
 func (d *DB) UpdateTags() error {
-	booksColl := d.session.DB(DB_NAME).C(BOOKS_COLL)
-	mr := NewMR(d.session.DB(DB_NAME))
-	return mr.UpdateTags(booksColl)
+	var u DBUpdate
+	u.src = d.session.DB(DB_NAME).C(BOOKS_COLL)
+	u.dst = d.session.DB(DB_NAME).C(TAGS_COLL)
+	return u.UpdateTags()
 }
 
 type Visits struct {
@@ -266,9 +269,10 @@ func (d *DB) GetHourVisits() ([]Visits, error) {
 }
 
 func (d *DB) UpdateHourVisits() error {
-	statsColl := d.session.DB(DB_NAME).C(STATS_COLL)
-	mr := NewMR(d.session.DB(DB_NAME))
-	return mr.UpdateHourVisits(statsColl)
+	var u DBUpdate
+	u.src = d.session.DB(DB_NAME).C(STATS_COLL)
+	u.dst = d.session.DB(DB_NAME).C(HOURLY_VISITS_COLL)
+	return u.UpdateHourVisits()
 }
 
 func (d *DB) GetDayVisits() ([]Visits, error) {
@@ -277,9 +281,10 @@ func (d *DB) GetDayVisits() ([]Visits, error) {
 }
 
 func (d *DB) UpdateDayVisits() error {
-	statsColl := d.session.DB(DB_NAME).C(STATS_COLL)
-	mr := NewMR(d.session.DB(DB_NAME))
-	return mr.UpdateDayVisits(statsColl)
+	var u DBUpdate
+	u.src = d.session.DB(DB_NAME).C(STATS_COLL)
+	u.dst = d.session.DB(DB_NAME).C(DAILY_VISITS_COLL)
+	return u.UpdateDayVisits()
 }
 
 func (d *DB) GetMonthVisits() ([]Visits, error) {
@@ -288,9 +293,10 @@ func (d *DB) GetMonthVisits() ([]Visits, error) {
 }
 
 func (d *DB) UpdateMonthVisits() error {
-	statsColl := d.session.DB(DB_NAME).C(STATS_COLL)
-	mr := NewMR(d.session.DB(DB_NAME))
-	return mr.UpdateMonthVisits(statsColl)
+	var u DBUpdate
+	u.src = d.session.DB(DB_NAME).C(STATS_COLL)
+	u.dst = d.session.DB(DB_NAME).C(MONTHLY_VISITS_COLL)
+	return u.UpdateMonthVisits()
 }
 
 func (d *DB) GetHourDownloads() ([]Visits, error) {
@@ -299,9 +305,10 @@ func (d *DB) GetHourDownloads() ([]Visits, error) {
 }
 
 func (d *DB) UpdateHourDownloads() error {
-	statsColl := d.session.DB(DB_NAME).C(STATS_COLL)
-	mr := NewMR(d.session.DB(DB_NAME))
-	return mr.UpdateHourDownloads(statsColl)
+	var u DBUpdate
+	u.src = d.session.DB(DB_NAME).C(STATS_COLL)
+	u.dst = d.session.DB(DB_NAME).C(HOURLY_DOWNLOADS_COLL)
+	return u.UpdateHourDownloads()
 }
 
 func (d *DB) GetDayDownloads() ([]Visits, error) {
@@ -310,9 +317,10 @@ func (d *DB) GetDayDownloads() ([]Visits, error) {
 }
 
 func (d *DB) UpdateDayDownloads() error {
-	statsColl := d.session.DB(DB_NAME).C(STATS_COLL)
-	mr := NewMR(d.session.DB(DB_NAME))
-	return mr.UpdateDayDownloads(statsColl)
+	var u DBUpdate
+	u.src = d.session.DB(DB_NAME).C(STATS_COLL)
+	u.dst = d.session.DB(DB_NAME).C(DAILY_DOWNLOADS_COLL)
+	return u.UpdateDayDownloads()
 }
 
 func (d *DB) GetMonthDownloads() ([]Visits, error) {
@@ -321,7 +329,8 @@ func (d *DB) GetMonthDownloads() ([]Visits, error) {
 }
 
 func (d *DB) UpdateMonthDownloads() error {
-	statsColl := d.session.DB(DB_NAME).C(STATS_COLL)
-	mr := NewMR(d.session.DB(DB_NAME))
-	return mr.UpdateMonthDownloads(statsColl)
+	var u DBUpdate
+	u.src = d.session.DB(DB_NAME).C(STATS_COLL)
+	u.dst = d.session.DB(DB_NAME).C(MONTHLY_DOWNLOADS_COLL)
+	return u.UpdateMonthDownloads()
 }
diff --git a/mapreduce.go b/db_stats.go
similarity index 51%
rename from mapreduce.go
rename to db_stats.go
index 83ed2f9..1394e81 100644
--- a/mapreduce.go
+++ b/db_stats.go
@@ -6,11 +6,16 @@ import (
 	"time"
 )
 
-func GetTags(numTags int, tagsColl *mgo.Collection) ([]string, error) {
+type DBUpdate struct {
+	src *mgo.Collection
+	dst *mgo.Collection
+}
+
+func GetTags(tagsColl *mgo.Collection) ([]string, error) {
 	var result []struct {
 		Tag string "_id"
 	}
-	err := tagsColl.Find(nil).Sort("-count").Limit(numTags).All(&result)
+	err := tagsColl.Find(nil).Sort("-count").All(&result)
 	if err != nil {
 		return nil, err
 	}
@@ -22,11 +27,11 @@ func GetTags(numTags int, tagsColl *mgo.Collection) ([]string, error) {
 	return tags, nil
 }
 
-func GetBooksVisited(num int, visitedColl *mgo.Collection) ([]bson.ObjectId, error) {
+func GetBooksVisited(visitedColl *mgo.Collection) ([]bson.ObjectId, error) {
 	var result []struct {
 		Book bson.ObjectId "_id"
 	}
-	err := visitedColl.Find(nil).Sort("-count").Limit(num).All(&result)
+	err := visitedColl.Find(nil).Sort("-count").All(&result)
 	if err != nil {
 		return nil, err
 	}
@@ -44,22 +49,12 @@ func GetVisits(visitsColl *mgo.Collection) ([]Visits, error) {
 	return result, err
 }
 
-type MR struct {
-	database *mgo.Database
-}
-
-func NewMR(database *mgo.Database) *MR {
-	m := new(MR)
-	m.database = database
-	return m
-}
-
-func (m *MR) UpdateTags(booksColl *mgo.Collection) error {
+func (u *DBUpdate) UpdateTags() error {
 	var tags []struct {
 		Tag   string "_id"
 		Count int    "count"
 	}
-	err := booksColl.Pipe([]bson.M{
+	err := u.src.Pipe([]bson.M{
 		{"$project": bson.M{"subject": 1}},
 		{"$unwind": "$subject"},
 		{"$group": bson.M{"_id": "$subject", "count": bson.M{"$sum": 1}}},
@@ -70,10 +65,9 @@ func (m *MR) UpdateTags(booksColl *mgo.Collection) error {
 		return err
 	}
 
-	tagsColl := m.database.C(TAGS_COLL)
-	tagsColl.DropCollection()
+	u.dst.DropCollection()
 	for _, tag := range tags {
-		err = tagsColl.Insert(tag)
+		err = u.dst.Insert(tag)
 		if err != nil {
 			return err
 		}
@@ -81,15 +75,7 @@ func (m *MR) UpdateTags(booksColl *mgo.Collection) error {
 	return nil
 }
 
-func (m *MR) UpdateMostVisited(statsColl *mgo.Collection) error {
-	return m.updateMostBooks(statsColl, "book", VISITED_COLL)
-}
-
-func (m *MR) UpdateMostDownloaded(statsColl *mgo.Collection) error {
-	return m.updateMostBooks(statsColl, "download", DOWNLOADED_COLL)
-}
-
-func (m *MR) updateMostBooks(statsColl *mgo.Collection, section string, resColl string) error {
+func (u *DBUpdate) UpdateMostBooks(section string) error {
 	const numDays = 30
 	start := time.Now().UTC().Add(-numDays * 24 * time.Hour)
 
@@ -97,7 +83,7 @@ func (m *MR) updateMostBooks(statsColl *mgo.Collection, section string, resColl
 		Book  string "_id"
 		Count int    "count"
 	}
-	err := statsColl.Pipe([]bson.M{
+	err := u.src.Pipe([]bson.M{
 		{"$match": bson.M{"date": bson.M{"$gt": start}, "section": section}},
 		{"$project": bson.M{"id": 1}},
 		{"$group": bson.M{"_id": "$id", "count": bson.M{"$sum": 1}}},
@@ -108,10 +94,9 @@ func (m *MR) updateMostBooks(statsColl *mgo.Collection, section string, resColl
 		return err
 	}
 
-	coll := m.database.C(resColl)
-	coll.DropCollection()
+	u.dst.DropCollection()
 	for _, book := range books {
-		err = coll.Insert(book)
+		err = u.dst.Insert(book)
 		if err != nil {
 			return err
 		}
@@ -119,84 +104,83 @@ func (m *MR) updateMostBooks(statsColl *mgo.Collection, section string, resColl
 	return nil
 }
 
-func (m *MR) UpdateHourVisits(statsColl *mgo.Collection) error {
+func (u *DBUpdate) UpdateHourVisits() error {
 	f := func(t time.Time) time.Time {
 		const span = time.Hour
 		return t.Add(span).Truncate(span)
 	}
 	const numDays = 2
 	spanStore := numDays * 24 * time.Hour
-	return m.updateVisits(f, spanStore, HOURLY_VISITS_COLL, true)
+	return u.updateVisits(f, spanStore, HOURLY_VISITS_COLL, true)
 }
 
-func (m *MR) UpdateDayVisits(statsColl *mgo.Collection) error {
+func (u *DBUpdate) UpdateDayVisits() error {
 	f := func(t time.Time) time.Time {
 		const span = 24 * time.Hour
 		return t.Add(span).Truncate(span)
 	}
 	const numDays = 30
 	spanStore := numDays * 24 * time.Hour
-	return m.updateVisits(f, spanStore, DAILY_VISITS_COLL, true)
+	return u.updateVisits(f, spanStore, DAILY_VISITS_COLL, true)
 }
 
-func (m *MR) UpdateMonthVisits(statsColl *mgo.Collection) error {
+func (u *DBUpdate) UpdateMonthVisits() error {
 	f := func(t time.Time) time.Time {
 		const span = 24 * time.Hour
 		return t.AddDate(0, 1, 1-t.Day()).Truncate(span)
 	}
 	const numDays = 365
 	spanStore := numDays * 24 * time.Hour
-	return m.updateVisits(f, spanStore, MONTHLY_VISITS_COLL, true)
+	return u.updateVisits(f, spanStore, MONTHLY_VISITS_COLL, true)
 }
 
-func (m *MR) UpdateHourDownloads(statsColl *mgo.Collection) error {
+func (u *DBUpdate) UpdateHourDownloads() error {
 	f := func(t time.Time) time.Time {
 		const span = time.Hour
 		return t.Add(span).Truncate(span)
 	}
 	const numDays = 2
 	spanStore := numDays * 24 * time.Hour
-	return m.updateVisits(f, spanStore, HOURLY_DOWNLOADS_COLL, false)
+	return u.updateVisits(f, spanStore, HOURLY_DOWNLOADS_COLL, false)
 }
 
-func (m *MR) UpdateDayDownloads(statsColl *mgo.Collection) error {
+func (u *DBUpdate) UpdateDayDownloads() error {
 	f := func(t time.Time) time.Time {
 		const span = 24 * time.Hour
 		return t.Add(span).Truncate(span)
 	}
 	const numDays = 30
 	spanStore := numDays * 24 * time.Hour
-	return m.updateVisits(f, spanStore, DAILY_DOWNLOADS_COLL, false)
+	return u.updateVisits(f, spanStore, DAILY_DOWNLOADS_COLL, false)
 }
 
-func (m *MR) UpdateMonthDownloads(statsColl *mgo.Collection) error {
+func (u *DBUpdate) UpdateMonthDownloads() error {
 	f := func(t time.Time) time.Time {
 		const span = 24 * time.Hour
 		return t.AddDate(0, 1, 1-t.Day()).Truncate(span)
 	}
 	const numDays = 365
 	spanStore := numDays * 24 * time.Hour
-	return m.updateVisits(f, spanStore, MONTHLY_DOWNLOADS_COLL, false)
+	return u.updateVisits(f, spanStore, MONTHLY_DOWNLOADS_COLL, false)
 }
 
-func (m *MR) updateVisits(incTime func(time.Time) time.Time, spanStore time.Duration, coll string, useSession bool) error {
-	storeColl := m.database.C(coll)
-	start := m.calculateStart(spanStore, storeColl)
+func (u *DBUpdate) updateVisits(incTime func(time.Time) time.Time, spanStore time.Duration, coll string, useSession bool) error {
+	start := u.calculateStart(spanStore)
 	for start.Before(time.Now().UTC()) {
 		stop := incTime(start)
 
 		var count int
 		var err error
 		if useSession {
-			count = m.countVisits(start, stop)
+			count = u.countVisits(start, stop)
 		} else {
-			count, err = m.countDownloads(start, stop)
+			count, err = u.countDownloads(start, stop)
 		}
 		if err != nil {
 			return err
 		}
 
-		err = storeColl.Insert(bson.M{"date": start, "count": count})
+		err = u.dst.Insert(bson.M{"date": start, "count": count})
 		if err != nil {
 			return err
 		}
@@ -204,29 +188,28 @@ func (m *MR) updateVisits(incTime func(time.Time) time.Time, spanStore time.Dura
 		start = stop
 	}
 
-	_, err := storeColl.RemoveAll(bson.M{"date": bson.M{"$lt": time.Now().UTC().Add(-spanStore)}})
+	_, err := u.dst.RemoveAll(bson.M{"date": bson.M{"$lt": time.Now().UTC().Add(-spanStore)}})
 	return err
 }
 
-func (m *MR) calculateStart(spanStore time.Duration, storeColl *mgo.Collection) time.Time {
+func (u *DBUpdate) calculateStart(spanStore time.Duration) time.Time {
 	var date struct {
 		Id   bson.ObjectId `bson:"_id"`
 		Date time.Time     `bson:"date"`
 	}
-	err := storeColl.Find(bson.M{}).Sort("-date").One(&date)
+	err := u.dst.Find(bson.M{}).Sort("-date").One(&date)
 	if err == nil {
-		storeColl.RemoveId(date.Id)
+		u.dst.RemoveId(date.Id)
 		return date.Date
 	}
 	return time.Now().UTC().Add(-spanStore).Truncate(time.Hour)
 }
 
-func (m *MR) countVisits(start time.Time, stop time.Time) int {
-	statsColl := m.database.C(STATS_COLL)
+func (u *DBUpdate) countVisits(start time.Time, stop time.Time) int {
 	var result struct {
 		Count int "count"
 	}
-	err := statsColl.Pipe([]bson.M{
+	err := u.src.Pipe([]bson.M{
 		{"$match": bson.M{"date": bson.M{"$gte": start, "$lt": stop}}},
 		{"$group": bson.M{"_id": "$session"}},
 		{"$group": bson.M{"_id": 1, "count": bson.M{"$sum": 1}}},
@@ -238,24 +221,7 @@ func (m *MR) countVisits(start time.Time, stop time.Time) int {
 	return result.Count
 }
 
-func (m *MR) countDownloads(start time.Time, stop time.Time) (int, error) {
+func (u *DBUpdate) countDownloads(start time.Time, stop time.Time) (int, error) {
 	query := bson.M{"date": bson.M{"$gte": start, "$lt": stop}, "section": "download"}
-	statsColl := m.database.C(STATS_COLL)
-	return statsColl.Find(query).Count()
-}
-
-func (m *MR) update(mr *mgo.MapReduce, query bson.M, queryColl *mgo.Collection, storeColl string) error {
-	metaColl := m.database.C(META_COLL)
-	_, err := metaColl.RemoveAll(bson.M{"type": storeColl})
-	if err != nil {
-		return err
-	}
-
-	mr.Out = bson.M{"replace": storeColl}
-	_, err = queryColl.Find(query).MapReduce(mr, nil)
-	if err != nil {
-		return err
-	}
-
-	return metaColl.Insert(bson.M{"type": storeColl})
+	return u.src.Find(query).Count()
 }
diff --git a/trantor.go b/trantor.go
index 36560ce..a226b74 100644
--- a/trantor.go
+++ b/trantor.go
@@ -127,12 +127,12 @@ type indexData struct {
 func indexHandler(h handler) {
 	var data indexData
 
-	data.Tags, _ = h.db.GetTags(TAGS_DISPLAY)
+	data.Tags, _ = h.db.GetTags()
 	data.S = GetStatus(h)
 	data.S.Home = true
 	data.Books, data.Count, _ = h.db.GetBooks(bson.M{"active": true}, BOOKS_FRONT_PAGE)
-	data.VisitedBooks, _ = h.db.GetVisitedBooks(BOOKS_FRONT_PAGE)
-	data.DownloadedBooks, _ = h.db.GetDownloadedBooks(BOOKS_FRONT_PAGE)
+	data.VisitedBooks, _ = h.db.GetVisitedBooks()
+	data.DownloadedBooks, _ = h.db.GetDownloadedBooks()
 	data.News = getNews(1, DAYS_NEWS_INDEXPAGE, h.db)
 	loadTemplate(h.w, "index", data)
 }