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Loaded up 21M edges, all of film data + names. And ran a complex quer… 

…y, with a 60ms latency!
1 parent 879a332 commit ca369823b241dc5c7fc7014b9a320858ed4da504 @manishrjain manishrjain committed
Unified Split
Showing with 95 additions and 9 deletions.
  1. +10 −2 commit/log.go
  2. +1 −0 notes.txt
  3. +25 −0 posting/list.go
  4. +4 −1 posting/lists.go
  5. +5 −2 server/loader/main.go
  6. +21 −4 server/main.go
  7. +29 −0 server/notes.txt
View
12 commit/log.go
@@ -243,6 +243,7 @@ func lastTimestamp(path string) (int64, error) {
return 0, err
}
+ discard := make([]byte, 4096)
reader := bufio.NewReaderSize(f, 2<<20)
var maxTs int64
header := make([]byte, 16)
@@ -277,7 +278,10 @@ func lastTimestamp(path string) (int64, error) {
}).Fatal("Log file doesn't have monotonically increasing records.")
}
- reader.Discard(int(h.size))
+ for int(h.size) > len(discard) {
+ discard = make([]byte, len(discard)*2)
+ }
+ reader.Read(discard[:int(h.size)])
}
return maxTs, nil
}
@@ -396,6 +400,7 @@ func streamEntriesInFile(path string,
}
defer f.Close()
+ discard := make([]byte, 4096)
reader := bufio.NewReaderSize(f, 5<<20)
header := make([]byte, 16)
for {
@@ -429,7 +434,10 @@ func streamEntriesInFile(path string,
ch <- data
} else {
- reader.Discard(int(hdr.size))
+ for int(hdr.size) > len(discard) {
+ discard = make([]byte, len(discard)*2)
+ }
+ reader.Read(discard[:int(hdr.size)])
}
}
return nil
View
1 notes.txt
@@ -0,0 +1 @@
+Have to increase the file limit set in Ubuntu to avoid the "too many open files" issue, probably caused by goroutines opening up RocksDB SST files.
View
25 posting/list.go
@@ -85,6 +85,22 @@ func (pa ByUid) Len() int { return len(pa) }
func (pa ByUid) Swap(i, j int) { pa[i], pa[j] = pa[j], pa[i] }
func (pa ByUid) Less(i, j int) bool { return pa[i].Uid() < pa[j].Uid() }
+func samePosting(a *types.Posting, b *types.Posting) bool {
+ if a.Uid() != b.Uid() {
+ return false
+ }
+ if a.ValueLength() != b.ValueLength() {
+ return false
+ }
+ if !bytes.Equal(a.ValueBytes(), b.ValueBytes()) {
+ return false
+ }
+ if !bytes.Equal(a.Source(), b.Source()) {
+ return false
+ }
+ return true
+}
+
// key = (entity uid, attribute)
func Key(uid uint64, attr string) []byte {
buf := new(bytes.Buffer)
@@ -455,6 +471,15 @@ func (l *List) mergeMutation(mp *types.Posting) {
} else { // curUid not found in mindex.
if inPlist { // In plist, so just set it in mlayer.
+ // If this posting matches what we already have in posting list,
+ // we don't need to `dirty` this by adding to mlayer.
+ plist := l.getPostingList()
+ var cp types.Posting
+ if ok := plist.Postings(&cp, pi); ok {
+ if samePosting(&cp, mp) {
+ return // do nothing.
+ }
+ }
l.mlayer[pi] = *mp
} else { // not in plist, not in mindex, so insert in mindex.
View
5 posting/lists.go
@@ -19,6 +19,7 @@ package posting
import (
"math/rand"
"runtime"
+ "runtime/debug"
"sync"
"sync/atomic"
"time"
@@ -57,7 +58,7 @@ var MIB uint64
func checkMemoryUsage() {
MIB = 1 << 20
- MAX_MEMORY = 2 * (1 << 30)
+ MAX_MEMORY = 3 * (1 << 30)
for _ = range time.Tick(5 * time.Second) {
var ms runtime.MemStats
@@ -78,6 +79,8 @@ func checkMemoryUsage() {
glog.Info("Merged lists. Calling GC.")
runtime.GC() // Call GC to do some cleanup.
+ glog.Info("Trying to free OS memory")
+ debug.FreeOSMemory()
runtime.ReadMemStats(&ms)
megs = ms.Alloc / MIB
View
7 server/loader/main.go
@@ -58,8 +58,11 @@ func main() {
}
logrus.SetLevel(logrus.InfoLevel)
- numCpus := runtime.GOMAXPROCS(-1)
- glog.WithField("gomaxprocs", numCpus).Info("Number of CPUs")
+ numCpus := runtime.NumCPU()
+ prevProcs := runtime.GOMAXPROCS(numCpus)
+ glog.WithField("num_cpu", numCpus).
+ WithField("prev_maxprocs", prevProcs).
+ Info("Set max procs to num cpus")
if len(*rdfGzips) == 0 {
glog.Fatal("No RDF GZIP files specified")
View
25 server/main.go
@@ -22,6 +22,7 @@ import (
"io/ioutil"
"net/http"
"runtime"
+ "time"
"github.com/Sirupsen/logrus"
"github.com/dgraph-io/dgraph/commit"
@@ -51,14 +52,16 @@ func queryHandler(w http.ResponseWriter, r *http.Request) {
x.SetStatus(w, x.E_INVALID_REQUEST, "Invalid request encountered.")
return
}
- glog.WithField("q", string(q)).Info("Query received.")
+ glog.WithField("q", string(q)).Debug("Query received.")
+ now := time.Now()
sg, err := gql.Parse(string(q))
if err != nil {
x.Err(glog, err).Error("While parsing query")
x.SetStatus(w, x.E_INVALID_REQUEST, err.Error())
return
}
- glog.WithField("q", string(q)).Info("Query parsed.")
+ parseLat := time.Since(now)
+ glog.WithField("q", string(q)).Debug("Query parsed.")
rch := make(chan error)
go query.ProcessGraph(sg, rch)
err = <-rch
@@ -67,13 +70,23 @@ func queryHandler(w http.ResponseWriter, r *http.Request) {
x.SetStatus(w, x.E_ERROR, err.Error())
return
}
- glog.WithField("q", string(q)).Info("Graph processed.")
+ processLat := time.Since(now)
+ glog.WithField("q", string(q)).Debug("Graph processed.")
js, err := sg.ToJson()
if err != nil {
x.Err(glog, err).Error("While converting to Json.")
x.SetStatus(w, x.E_ERROR, err.Error())
return
}
+ jsonLat := time.Since(now)
+ glog.WithFields(logrus.Fields{
+ "total": time.Since(now),
+ "parsing": parseLat.String(),
+ "process": processLat - parseLat,
+ "json": jsonLat - processLat,
+ }).Info("Query Latencies")
+
+ glog.WithField("latency", time.Since(now).String()).Info("Query Latency")
w.Header().Set("Content-Type", "application/json")
fmt.Fprint(w, string(js))
}
@@ -84,7 +97,11 @@ func main() {
glog.Fatal("Unable to parse flags")
}
logrus.SetLevel(logrus.InfoLevel)
- glog.WithField("gomaxprocs", runtime.GOMAXPROCS(-1)).Info("Number of CPUs")
+ numCpus := runtime.NumCPU()
+ prev := runtime.GOMAXPROCS(numCpus)
+ glog.WithField("num_cpu", numCpus).
+ WithField("prev_maxprocs", prev).
+ Info("Set max procs to num cpus")
ps := new(store.Store)
ps.Init(*postingDir)
View
29 server/notes.txt
@@ -0,0 +1,29 @@
+curl localhost:8080/query -XPOST -d '{
+me(_xid_: m.06pj8) {
+ type.object.name.en
+ film.director.film {
+ type.object.name.en
+ film.film.starring {
+ film.performance.actor {
+ film.director.film {
+ type.object.name.en
+ }
+ type.object.name.en
+ }
+ }
+ film.film.initial_release_date
+ film.film.country
+ film.film.genre {
+ type.object.name.en
+ }
+ }
+}
+}' > output.json
+
+INFO[0554] Query Latencies json=35.434904ms package=server parsing=93.385µs process=24.785928ms total=60.314523ms
+
+The first time this query runs, it's a bit slower, taking around 250ms in processing, mostly because we have to load
+the posting lists from rocksdb, and use disk seeks. But, on consecutive runs, when the PLs are already in memory,
+this takes under 25ms for processing. IT actually takes more time to convert the results to JSON!
+
+My reactions are mixed. I'm happy, but unsatisfied.

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