WIP

src/go/mongolib/fingerprinter/figerprinter.go

@@ -0,0 +1,115 @@
+package fingerprinter
+
+import (
+	"encoding/json"
+	"fmt"
+	"regexp"
+	"sort"
+	"strings"
+
+	"github.com/percona/percona-toolkit/src/go/mongolib/util"
+)
+
+var (
+	MAX_DEPTH_LEVEL     = 10
+	DEFAULT_KEY_FILTERS = []string{"^shardVersion$", "^\\$"}
+)
+
+type Fingerprinter interface {
+	Fingerprint(query map[string]interface{}) (string, error)
+}
+
+type Fingerprint struct {
+	keyFilters []string
+}
+
+func NewFingerprinter(keyFilters []string) *Fingerprint {
+	return &Fingerprint{
+		keyFilters: keyFilters,
+	}
+}
+
+// Query is the top level map query element
+// Example for MongoDB 3.2+
+//     "query" : {
+//        "find" : "col1",
+//        "filter" : {
+//            "s2" : {
+//                "$lt" : "54701",
+//                "$gte" : "73754"
+//            }
+//        },
+//        "sort" : {
+//            "user_id" : 1
+//        }
+//     }
+func (f *Fingerprint) Fingerprint(query map[string]interface{}) (string, error) {
+
+	realQuery, err := util.GetQueryField(query)
+	if err != nil {
+		// Try to encode doc.Query as json for prettiness
+		if buf, err := json.Marshal(realQuery); err == nil {
+			return "", fmt.Errorf("%v for query %s", err, string(buf))
+		}
+		// If we cannot encode as json, return just the error message without the query
+		return "", err
+	}
+	retKeys := keys(realQuery, f.keyFilters)
+
+	sort.Strings(retKeys)
+
+	// if there is a sort clause in the query, we have to add all fields in the sort
+	// fields list that are not in the query keys list (retKeys)
+	if sortKeys, ok := query["sort"]; ok {
+		if sortKeysMap, ok := sortKeys.(map[string]interface{}); ok {
+			sortKeys := keys(sortKeysMap, f.keyFilters)
+			for _, sortKey := range sortKeys {
+				if !inSlice(sortKey, retKeys) {
+					retKeys = append(retKeys, sortKey)
+				}
+			}
+		}
+	}
+
+	return strings.Join(retKeys, ","), nil
+}
+
+func inSlice(str string, list []string) bool {
+	for _, v := range list {
+		if v == str {
+			return true
+		}
+	}
+	return false
+}
+
+func keys(query map[string]interface{}, keyFilters []string) []string {
+	return getKeys(query, keyFilters, 0)
+}
+
+func getKeys(query map[string]interface{}, keyFilters []string, level int) []string {
+	ks := []string{}
+	for key, value := range query {
+		if shouldSkipKey(key, keyFilters) {
+			continue
+		}
+		ks = append(ks, key)
+		if m, ok := value.(map[string]interface{}); ok {
+			level++
+			if level <= MAX_DEPTH_LEVEL {
+				ks = append(ks, getKeys(m, keyFilters, level)...)
+			}
+		}
+	}
+	sort.Strings(ks)
+	return ks
+}
+
+func shouldSkipKey(key string, keyFilters []string) bool {
+	for _, filter := range keyFilters {
+		if matched, _ := regexp.MatchString(filter, key); matched {
+			return true
+		}
+	}
+	return false
+}

src/go/mongolib/profiler/profiler.go

@@ -0,0 +1,176 @@
+package profiler
+
+import (
+	"crypto/md5"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/percona/percona-toolkit/src/go/mongolib/fingerprinter"
+	"github.com/percona/percona-toolkit/src/go/mongolib/proto"
+	"github.com/percona/percona-toolkit/src/go/mongolib/util"
+	"github.com/percona/percona-toolkit/src/go/pt-mongodb-query-digest/filter"
+	"github.com/prometheus/common/log"
+)
+
+var (
+	MAX_DEPTH_LEVEL        = 10
+	CANNOT_GET_QUERY_ERROR = errors.New("cannot get query field from the profile document (it is not a map)")
+)
+
+type Times []time.Time
+
+func (a Times) Len() int           { return len(a) }
+func (a Times) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a Times) Less(i, j int) bool { return a[i].Before(a[j]) }
+
+type StatsGroupKey struct {
+	Operation   string
+	Fingerprint string
+	Namespace   string
+}
+
+type Stat struct {
+	BlockedTime    Times
+	Count          int
+	Fingerprint    string
+	FirstSeen      time.Time
+	ID             string
+	LastSeen       time.Time
+	LockTime       Times
+	NReturned      []float64
+	NScanned       []float64
+	Namespace      string
+	Operation      string
+	Query          map[string]interface{}
+	QueryTime      []float64 // in milliseconds
+	ResponseLength []float64
+	TableScan      bool
+}
+
+type Iter interface {
+	All(result interface{}) error
+	Close() error
+	Err() error
+	For(result interface{}, f func() error) (err error)
+	Next(result interface{}) bool
+	Timeout() bool
+}
+
+type Profiler interface {
+	StatsChan() chan []Stat
+	Start()
+	Stop()
+}
+
+type Profile struct {
+	filters       []filter.Filter
+	iterator      Iter
+	ticker        chan time.Time
+	statsChan     chan []Stat
+	stopChan      chan bool
+	stats         []Stat
+	keyFilters    []string
+	fingerprinter fingerprinter.Fingerprinter
+}
+
+func NewProfiler(iterator Iter, filters []filter.Filter, ticker chan time.Time, fp fingerprinter.Fingerprinter) Profiler {
+	return &Profile{
+		filters:       filters,
+		fingerprinter: fp,
+		iterator:      iterator,
+		ticker:        ticker,
+		statsChan:     make(chan []Stat),
+		stats:         make([]Stat, 100),
+		keyFilters:    []string{"^shardVersion$", "^\\$"},
+	}
+}
+
+func (p *Profile) StatsChan() chan []Stat {
+	return p.statsChan
+}
+
+func (p *Profile) Start() {
+	go p.getData()
+}
+
+func (p *Profile) Stop() {
+	p.stopChan <- true
+}
+
+func (p *Profile) getData() {
+	var doc proto.SystemProfile
+	stop := false
+	stats := make(map[StatsGroupKey]*Stat)
+
+	for !stop && p.iterator.Next(&doc) && p.iterator.Err() == nil {
+		valid := true
+		for _, filter := range p.filters {
+			if filter(doc) == false {
+				valid = false
+				break
+			}
+		}
+		if !valid {
+			continue
+		}
+
+		select {
+		case <-p.ticker:
+			p.statsChan <- statsToArray(stats)
+		case <-p.stopChan:
+			stop = true
+			continue
+		default:
+			if len(doc.Query) > 0 {
+
+				fp, err := p.fingerprinter.Fingerprint(doc.Query)
+				if err != nil {
+					log.Errorf("cannot get fingerprint: %s", err.Error())
+					continue
+				}
+				var s *Stat
+				var ok bool
+				key := StatsGroupKey{
+					Operation:   doc.Op,
+					Fingerprint: fp,
+					Namespace:   doc.Ns,
+				}
+				if s, ok = stats[key]; !ok {
+					realQuery, _ := util.GetQueryField(doc.Query)
+					s = &Stat{
+						ID:          fmt.Sprintf("%x", md5.Sum([]byte(fmt.Sprintf("%s", key)))),
+						Operation:   doc.Op,
+						Fingerprint: fp,
+						Namespace:   doc.Ns,
+						TableScan:   false,
+						Query:       realQuery,
+					}
+					stats[key] = s
+				}
+				s.Count++
+				s.NScanned = append(s.NScanned, float64(doc.DocsExamined))
+				s.NReturned = append(s.NReturned, float64(doc.Nreturned))
+				s.QueryTime = append(s.QueryTime, float64(doc.Millis))
+				s.ResponseLength = append(s.ResponseLength, float64(doc.ResponseLength))
+				var zeroTime time.Time
+				if s.FirstSeen == zeroTime || s.FirstSeen.After(doc.Ts) {
+					s.FirstSeen = doc.Ts
+				}
+				if s.LastSeen == zeroTime || s.LastSeen.Before(doc.Ts) {
+					s.LastSeen = doc.Ts
+				}
+			}
+		}
+	}
+
+	p.statsChan <- statsToArray(stats)
+}
+
+func statsToArray(stats map[StatsGroupKey]*Stat) []Stat {
+	sa := make([]Stat, len(stats))
+	for _, s := range stats {
+		sa = append(sa, *s)
+	}
+	return sa
+}

src/go/mongolib/util/util.go

@@ -12,6 +12,10 @@ import (
 	"gopkg.in/mgo.v2/bson"
 )
 
+var (
+	CANNOT_GET_QUERY_ERROR = errors.New("cannot get query field from the profile document (it is not a map)")
+)
+
 func GetReplicasetMembers(dialer pmgo.Dialer, di *pmgo.DialInfo) ([]proto.Members, error) {
 	hostnames, err := GetHostnames(dialer, di)
 	if err != nil {
@@ -232,3 +236,22 @@ func GetServerStatus(dialer pmgo.Dialer, di *pmgo.DialInfo, hostname string) (pr
 
 	return ss, nil
 }
+
+func GetQueryField(query map[string]interface{}) (map[string]interface{}, error) {
+	// MongoDB 3.0
+	if squery, ok := query["$query"]; ok {
+		// just an extra check to ensure this type assertion won't fail
+		if ssquery, ok := squery.(map[string]interface{}); ok {
+			return ssquery, nil
+		}
+		return nil, CANNOT_GET_QUERY_ERROR
+	}
+	// MongoDB 3.2+
+	if squery, ok := query["filter"]; ok {
+		if ssquery, ok := squery.(map[string]interface{}); ok {
+			return ssquery, nil
+		}
+		return nil, CANNOT_GET_QUERY_ERROR
+	}
+	return query, nil
+}

src/go/pt-mongodb-query-digest/filter/filters.go

@@ -0,0 +1,23 @@
+package filter
+
+import (
+	"strings"
+
+	"github.com/percona/percona-toolkit/src/go/mongolib/proto"
+)
+
+type Filter func(proto.SystemProfile) bool
+
+// This func receives a doc from the profiler and returns:
+// true : the document must be considered
+// false: the document must be skipped
+func NewFilterByCollection(collectionsToSkip []string) func(proto.SystemProfile) bool {
+	return func(doc proto.SystemProfile) bool {
+		for _, collection := range collectionsToSkip {
+			if strings.HasSuffix(doc.Ns, collection) {
+				return false
+			}
+		}
+		return true
+	}
+}

src/go/pt-mongodb-query-digest/main.go

@@ -1,25 +1,24 @@
 package main
 
 import (
-	"crypto/md5"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"os"
-	"regexp"
 	"sort"
 	"strings"
 	"text/template"
 	"time"
 
 	"github.com/howeyc/gopass"
-	"github.com/kr/pretty"
 	"github.com/montanaflynn/stats"
 	"github.com/pborman/getopt"
 	"github.com/percona/percona-toolkit/src/go/lib/config"
 	"github.com/percona/percona-toolkit/src/go/lib/versioncheck"
+	"github.com/percona/percona-toolkit/src/go/mongolib/fingerprinter"
+	"github.com/percona/percona-toolkit/src/go/mongolib/profiler"
 	"github.com/percona/percona-toolkit/src/go/mongolib/proto"
 	"github.com/percona/percona-toolkit/src/go/mongolib/util"
+	"github.com/percona/percona-toolkit/src/go/pt-mongodb-query-digest/filter"
 	"github.com/percona/pmgo"
 	log "github.com/sirupsen/logrus"
 	"gopkg.in/mgo.v2"
@@ -27,8 +26,7 @@ import (
 )
 
 const (
-	TOOLNAME        = "pt-mongodb-query-digest"
-	MAX_DEPTH_LEVEL = 10
+	TOOLNAME = "pt-mongodb-query-digest"
 
 	DEFAULT_AUTHDB          = "admin"
 	DEFAULT_HOST            = "localhost:27017"
@@ -41,24 +39,8 @@ var (
 	Build     string = "01-01-1980"
 	GoVersion string = "1.8"
 	Version   string = "3.0.1"
-
-	CANNOT_GET_QUERY_ERROR = errors.New("cannot get query field from the profile document (it is not a map)")
-
-	// This is a regexp array to filter out the keys we don't want in the fingerprint
-	keyFilters = func() []string {
-		return []string{"^shardVersion$", "^\\$"}
-	}
 )
 
-type iter interface {
-	All(result interface{}) error
-	Close() error
-	Err() error
-	For(result interface{}, f func() error) (err error)
-	Next(result interface{}) bool
-	Timeout() bool
-}
-
 type options struct {
 	AuthDB          string
 	Database        string
@@ -82,42 +64,6 @@ type options struct {
 // false: the document must be skipped
 type docsFilter func(proto.SystemProfile) bool
 
-type statsArray []stat
-
-func (a statsArray) Len() int           { return len(a) }
-func (a statsArray) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
-func (a statsArray) Less(i, j int) bool { return a[i].Count < a[j].Count }
-
-type times []time.Time
-
-func (a times) Len() int           { return len(a) }
-func (a times) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
-func (a times) Less(i, j int) bool { return a[i].Before(a[j]) }
-
-type stat struct {
-	ID             string
-	Operation      string
-	Fingerprint    string
-	Namespace      string
-	Query          map[string]interface{}
-	Count          int
-	TableScan      bool
-	NScanned       []float64
-	NReturned      []float64
-	QueryTime      []float64 // in milliseconds
-	ResponseLength []float64
-	LockTime       times
-	BlockedTime    times
-	FirstSeen      time.Time
-	LastSeen       time.Time
-}
-
-type groupKey struct {
-	Operation   string
-	Fingerprint string
-	Namespace   string
-}
-
 type statistics struct {
 	Pct    float64
 	Total  float64
@@ -215,36 +161,22 @@ func main() {
 		fmt.Println("Using those documents for the stats")
 	}
 
-	filters := []docsFilter{}
+	opts.SkipCollections = sanitizeSkipCollections(opts.SkipCollections)
+	filters := []filter.Filter{}
 
 	if len(opts.SkipCollections) > 0 {
-		// Sanitize the param. using --skip-collections="" will produce an 1 element array but
-		// that element will be empty. The same would be using --skip-collections=a,,d
-		cols := []string{}
-		for _, c := range opts.SkipCollections {
-			if strings.TrimSpace(c) != "" {
-				cols = append(cols, c)
-			}
-		}
-		if len(cols) > 0 {
-			// This func receives a doc from the profiler and returns:
-			// true : the document must be considered
-			// false: the document must be skipped
-			filterSystemProfile := func(doc proto.SystemProfile) bool {
-				for _, collection := range cols {
-					if strings.HasSuffix(doc.Ns, collection) {
-						return false
-					}
-				}
-				return true
-			}
-			filters = append(filters, filterSystemProfile)
-		}
+		filters = append(filters, filter.NewFilterByCollection(opts.SkipCollections))
 	}
 
 	query := bson.M{"op": bson.M{"$nin": []string{"getmore", "delete"}}}
 	i := session.DB(di.Database).C("system.profile").Find(query).Sort("-$natural").Iter()
-	queries := sortQueries(getData(i, filters), opts.OrderBy)
+
+	fp := fingerprinter.NewFingerprinter(fingerprinter.DEFAULT_KEY_FILTERS)
+	prof := profiler.NewProfiler(i, filters, nil, fp)
+	prof.Start()
+	queries := <-prof.StatsChan()
+
+	queries = sortQueries(queries, opts.OrderBy)
 
 	uptime := uptime(session)
 
@@ -306,9 +238,9 @@ func uptime(session pmgo.SessionManager) int64 {
 	return ss.Uptime
 }
 
-func calcTotalQueryStats(queries []stat, uptime int64) queryInfo {
+func calcTotalQueryStats(queries []profiler.Stat, uptime int64) queryInfo {
 	qi := queryInfo{}
-	qs := stat{}
+	qs := profiler.Stat{}
 	_, totalScanned, totalReturned, totalQueryTime, totalBytes := calcTotals(queries)
 	for _, query := range queries {
 		qs.NScanned = append(qs.NScanned, query.NScanned...)
@@ -342,7 +274,7 @@ func calcTotalQueryStats(queries []stat, uptime int64) queryInfo {
 	return qi
 }
 
-func calcQueryStats(queries []stat, uptime int64) []queryInfo {
+func calcQueryStats(queries []profiler.Stat, uptime int64) []queryInfo {
 	queryStats := []queryInfo{}
 	_, totalScanned, totalReturned, totalQueryTime, totalBytes := calcTotals(queries)
 	for rank, query := range queries {
@@ -383,9 +315,9 @@ func calcQueryStats(queries []stat, uptime int64) []queryInfo {
 	return queryStats
 }
 
-func getTotals(queries []stat) stat {
+func getTotals(queries []profiler.Stat) profiler.Stat {
 
-	qt := stat{}
+	qt := profiler.Stat{}
 	for _, query := range queries {
 		qt.NScanned = append(qt.NScanned, query.NScanned...)
 		qt.NReturned = append(qt.NReturned, query.NReturned...)
@@ -396,7 +328,7 @@ func getTotals(queries []stat) stat {
 
 }
 
-func calcTotals(queries []stat) (totalCount int, totalScanned, totalReturned, totalQueryTime, totalBytes float64) {
+func calcTotals(queries []profiler.Stat) (totalCount int, totalScanned, totalReturned, totalQueryTime, totalBytes float64) {
 
 	for _, query := range queries {
 		totalCount += query.Count
@@ -428,78 +360,6 @@ func calcStats(samples []float64) statistics {
 	return s
 }
 
-func getData(i iter, filters []docsFilter) []stat {
-	var doc proto.SystemProfile
-	stats := make(map[groupKey]*stat)
-
-	log.Debug(`Documents returned by db.getSiblinfDB("<dbnamehere>").system.profile.Find({"op": {"$nin": []string{"getmore", "delete"}}).Sort("-$natural")`)
-
-	for i.Next(&doc) && i.Err() == nil {
-		valid := true
-		for _, filter := range filters {
-			if filter(doc) == false {
-				valid = false
-				break
-			}
-		}
-		if !valid {
-			continue
-		}
-
-		log.Debugln("====================================================================================================")
-		log.Debug(pretty.Sprint(doc))
-		if len(doc.Query) > 0 {
-
-			fp, err := fingerprint(doc.Query)
-			if err != nil {
-				log.Errorf("cannot get fingerprint: %s", err.Error())
-				continue
-			}
-			var s *stat
-			var ok bool
-			key := groupKey{
-				Operation:   doc.Op,
-				Fingerprint: fp,
-				Namespace:   doc.Ns,
-			}
-			if s, ok = stats[key]; !ok {
-				realQuery, _ := getQueryField(doc.Query)
-				s = &stat{
-					ID:          fmt.Sprintf("%x", md5.Sum([]byte(fmt.Sprintf("%s", key)))),
-					Operation:   doc.Op,
-					Fingerprint: fp,
-					Namespace:   doc.Ns,
-					TableScan:   false,
-					Query:       realQuery,
-				}
-				stats[key] = s
-			}
-			s.Count++
-			s.NScanned = append(s.NScanned, float64(doc.DocsExamined))
-			s.NReturned = append(s.NReturned, float64(doc.Nreturned))
-			s.QueryTime = append(s.QueryTime, float64(doc.Millis))
-			s.ResponseLength = append(s.ResponseLength, float64(doc.ResponseLength))
-			var zeroTime time.Time
-			if s.FirstSeen == zeroTime || s.FirstSeen.After(doc.Ts) {
-				s.FirstSeen = doc.Ts
-			}
-			if s.LastSeen == zeroTime || s.LastSeen.Before(doc.Ts) {
-				s.LastSeen = doc.Ts
-			}
-		}
-	}
-
-	// We need to sort the data but a hash cannot be sorted so, convert the hash having
-	// the results to a slice
-	sa := statsArray{}
-	for _, s := range stats {
-		sa = append(sa, *s)
-	}
-
-	sort.Sort(sa)
-	return sa
-}
-
 func getOptions() (*options, error) {
 	opts := &options{
 		Host:            DEFAULT_HOST,
@@ -600,121 +460,6 @@ func getDialInfo(opts *options) *pmgo.DialInfo {
 	return pmgoDialInfo
 }
 
-func getQueryField(query map[string]interface{}) (map[string]interface{}, error) {
-	// MongoDB 3.0
-	if squery, ok := query["$query"]; ok {
-		// just an extra check to ensure this type assertion won't fail
-		if ssquery, ok := squery.(map[string]interface{}); ok {
-			return ssquery, nil
-		}
-		return nil, CANNOT_GET_QUERY_ERROR
-	}
-	// MongoDB 3.2+
-	if squery, ok := query["filter"]; ok {
-		if ssquery, ok := squery.(map[string]interface{}); ok {
-			return ssquery, nil
-		}
-		return nil, CANNOT_GET_QUERY_ERROR
-	}
-	return query, nil
-}
-
-// Query is the top level map query element
-// Example for MongoDB 3.2+
-//     "query" : {
-//        "find" : "col1",
-//        "filter" : {
-//            "s2" : {
-//                "$lt" : "54701",
-//                "$gte" : "73754"
-//            }
-//        },
-//        "sort" : {
-//            "user_id" : 1
-//        }
-//     }
-func fingerprint(query map[string]interface{}) (string, error) {
-
-	realQuery, err := getQueryField(query)
-	if err != nil {
-		// Try to encode doc.Query as json for prettiness
-		if buf, err := json.Marshal(realQuery); err == nil {
-			return "", fmt.Errorf("%v for query %s", err, string(buf))
-		}
-		// If we cannot encode as json, return just the error message without the query
-		return "", err
-	}
-	retKeys := keys(realQuery, 0)
-
-	sort.Strings(retKeys)
-
-	// if there is a sort clause in the query, we have to add all fields in the sort
-	// fields list that are not in the query keys list (retKeys)
-	if sortKeys, ok := query["sort"]; ok {
-		if sortKeysMap, ok := sortKeys.(map[string]interface{}); ok {
-			sortKeys := mapKeys(sortKeysMap, 0)
-			for _, sortKey := range sortKeys {
-				if !inSlice(sortKey, retKeys) {
-					retKeys = append(retKeys, sortKey)
-				}
-			}
-		}
-	}
-
-	return strings.Join(retKeys, ","), nil
-}
-
-func inSlice(str string, list []string) bool {
-	for _, v := range list {
-		if v == str {
-			return true
-		}
-	}
-	return false
-}
-
-func keys(query map[string]interface{}, level int) []string {
-	ks := []string{}
-	for key, value := range query {
-		if shouldSkipKey(key) {
-			continue
-		}
-		ks = append(ks, key)
-		if m, ok := value.(map[string]interface{}); ok {
-			level++
-			if level <= MAX_DEPTH_LEVEL {
-				ks = append(ks, keys(m, level)...)
-			}
-		}
-	}
-	sort.Strings(ks)
-	return ks
-}
-
-func mapKeys(query map[string]interface{}, level int) []string {
-	ks := []string{}
-	for key, value := range query {
-		ks = append(ks, key)
-		if m, ok := value.(map[string]interface{}); ok {
-			level++
-			if level <= MAX_DEPTH_LEVEL {
-				ks = append(ks, keys(m, level)...)
-			}
-		}
-	}
-	sort.Strings(ks)
-	return ks
-}
-
-func shouldSkipKey(key string) bool {
-	for _, filter := range keyFilters() {
-		if matched, _ := regexp.MatchString(filter, key); matched {
-			return true
-		}
-	}
-	return false
-}
-
 func printHeader(opts *options) {
 	fmt.Printf("%s - %s\n", TOOLNAME, time.Now().Format(time.RFC1123Z))
 	fmt.Printf("Host: %s\n", opts.Host)
@@ -760,15 +505,15 @@ func getTotalsTemplate() string {
 	return t
 }
 
-type lessFunc func(p1, p2 *stat) bool
+type lessFunc func(p1, p2 *profiler.Stat) bool
 
 type multiSorter struct {
-	queries []stat
+	queries []profiler.Stat
 	less    []lessFunc
 }
 
 // Sort sorts the argument slice according to the less functions passed to OrderedBy.
-func (ms *multiSorter) Sort(queries []stat) {
+func (ms *multiSorter) Sort(queries []profiler.Stat) {
 	ms.queries = queries
 	sort.Sort(ms)
 }
@@ -817,23 +562,23 @@ func (ms *multiSorter) Less(i, j int) bool {
 	return ms.less[k](p, q)
 }
 
-func sortQueries(queries []stat, orderby []string) []stat {
+func sortQueries(queries []profiler.Stat, orderby []string) []profiler.Stat {
 	sortFuncs := []lessFunc{}
 	for _, field := range orderby {
 		var f lessFunc
 		switch field {
 		//
 		case "count":
-			f = func(c1, c2 *stat) bool {
+			f = func(c1, c2 *profiler.Stat) bool {
 				return c1.Count < c2.Count
 			}
 		case "-count":
-			f = func(c1, c2 *stat) bool {
+			f = func(c1, c2 *profiler.Stat) bool {
 				return c1.Count > c2.Count
 			}
 
 		case "ratio":
-			f = func(c1, c2 *stat) bool {
+			f = func(c1, c2 *profiler.Stat) bool {
 				ns1, _ := stats.Max(c1.NScanned)
 				ns2, _ := stats.Max(c2.NScanned)
 				nr1, _ := stats.Max(c1.NReturned)
@@ -843,7 +588,7 @@ func sortQueries(queries []stat, orderby []string) []stat {
 				return ratio1 < ratio2
 			}
 		case "-ratio":
-			f = func(c1, c2 *stat) bool {
+			f = func(c1, c2 *profiler.Stat) bool {
 				ns1, _ := stats.Max(c1.NScanned)
 				ns2, _ := stats.Max(c2.NScanned)
 				nr1, _ := stats.Max(c1.NReturned)
@@ -855,13 +600,13 @@ func sortQueries(queries []stat, orderby []string) []stat {
 
 		//
 		case "query-time":
-			f = func(c1, c2 *stat) bool {
+			f = func(c1, c2 *profiler.Stat) bool {
 				qt1, _ := stats.Max(c1.QueryTime)
 				qt2, _ := stats.Max(c2.QueryTime)
 				return qt1 < qt2
 			}
 		case "-query-time":
-			f = func(c1, c2 *stat) bool {
+			f = func(c1, c2 *profiler.Stat) bool {
 				qt1, _ := stats.Max(c1.QueryTime)
 				qt2, _ := stats.Max(c2.QueryTime)
 				return qt1 > qt2
@@ -869,13 +614,13 @@ func sortQueries(queries []stat, orderby []string) []stat {
 
 		//
 		case "docs-scanned":
-			f = func(c1, c2 *stat) bool {
+			f = func(c1, c2 *profiler.Stat) bool {
 				ns1, _ := stats.Max(c1.NScanned)
 				ns2, _ := stats.Max(c2.NScanned)
 				return ns1 < ns2
 			}
 		case "-docs-scanned":
-			f = func(c1, c2 *stat) bool {
+			f = func(c1, c2 *profiler.Stat) bool {
 				ns1, _ := stats.Max(c1.NScanned)
 				ns2, _ := stats.Max(c2.NScanned)
 				return ns1 > ns2
@@ -883,13 +628,13 @@ func sortQueries(queries []stat, orderby []string) []stat {
 
 		//
 		case "docs-returned":
-			f = func(c1, c2 *stat) bool {
+			f = func(c1, c2 *profiler.Stat) bool {
 				nr1, _ := stats.Max(c1.NReturned)
 				nr2, _ := stats.Max(c2.NReturned)
 				return nr1 < nr2
 			}
 		case "-docs-returned":
-			f = func(c1, c2 *stat) bool {
+			f = func(c1, c2 *profiler.Stat) bool {
 				nr1, _ := stats.Max(c1.NReturned)
 				nr2, _ := stats.Max(c2.NReturned)
 				return nr1 > nr2
@@ -951,3 +696,17 @@ func isReplicasetEnabled(session pmgo.SessionManager) bool {
 	}
 	return true
 }
+
+// Sanitize the param. using --skip-collections="" will produce an 1 element array but
+// that element will be empty. The same would be using --skip-collections=a,,d
+func sanitizeSkipCollections(skipCollections []string) []string {
+	cols := []string{}
+	if len(skipCollections) > 0 {
+		for _, c := range skipCollections {
+			if strings.TrimSpace(c) != "" {
+				cols = append(cols, c)
+			}
+		}
+	}
+	return cols
+}