puller: fix a memory leak bug in the frontier (#704)

pingcap · Jul 3, 2020 · 39bb362 · 39bb362
1 parent 0057782
commit 39bb362
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Showing 8 changed files with 605 additions and 281 deletions.
diff --git a/cdc/puller/frontier/frontier.go b/cdc/puller/frontier/frontier.go
@@ -16,6 +16,7 @@ package frontier
 import (
 	"bytes"
 	"fmt"
+	"math"
 	"strings"
 
 	"github.com/pingcap/ticdc/pkg/regionspan"
@@ -28,66 +29,41 @@ type Frontier interface {
 	String() string
 }
 
-type node struct {
-	start []byte
-	end   []byte
-	ts    uint64
-
-	// used by list
-	nexts []*node
-
-	// used by heap
-	left     *node
-	right    *node
-	children *node
-	parent   *node
-	rank     int
-	marked   bool
-}
-
-func (s *node) String() string {
-	return fmt.Sprintf("[{%s %s} @ %d]", s.start, s.end, s.ts)
-}
-
 // spanFrontier tracks the minimum timestamp of a set of spans.
 type spanFrontier struct {
-	list    spanList
-	minHeap minTsHeap
+	spanList  skipList
+	minTsHeap fibonacciHeap
 }
 
 // NewFrontier creates Froniter from the given spans.
-func NewFrontier(spans ...regionspan.Span) Frontier {
+func NewFrontier(checkpointTs uint64, spans ...regionspan.Span) Frontier {
 	// spanFrontier don't support use Nil as the maximum key of End range
 	// So we use set it as util.UpperBoundKey, the means the real use case *should not* have a
 	// End key bigger than util.UpperBoundKey
 	for i, span := range spans {
 		spans[i] = span.Hack()
 	}
 
-	s := &spanFrontier{}
-	s.list.init()
-
+	s := &spanFrontier{
+		spanList: *newSpanList(),
+	}
+	firstSpan := true
 	for _, span := range spans {
-		e := &node{
-			start: span.Start,
-			end:   span.End,
-			ts:    0,
+		if firstSpan {
+			s.spanList.Insert(span.Start, s.minTsHeap.Insert(checkpointTs))
+			s.spanList.Insert(span.End, s.minTsHeap.Insert(math.MaxUint64))
+			firstSpan = false
+			continue
 		}
-
-		s.list.insert(e)
-		s.minHeap.insert(e)
+		s.insert(span, checkpointTs)
 	}
 
 	return s
 }
 
 // Frontier return the minimum tiemstamp.
 func (s *spanFrontier) Frontier() uint64 {
-	min := s.minHeap.getMin()
-	if min == nil {
-		return 0
-	}
-	return min.ts
+	return s.minTsHeap.GetMinKey()
 }
 
 // Forward advances the timestamp for a span.
@@ -97,70 +73,67 @@ func (s *spanFrontier) Forward(span regionspan.Span, ts uint64) {
 }
 
 func (s *spanFrontier) insert(span regionspan.Span, ts uint64) {
-	n := s.list.seek(span.Start)
-
-	if n == nil || bytes.Compare(span.End, n.start) <= 0 {
-		// No overlapped spans.
-		return
-	}
-
-	if bytes.Compare(n.end, span.Start) <= 0 {
-		// Pointed span has no overlap, step to next.
-		n = n.next()
-	}
-
-	if n != nil && bytes.Compare(span.Start, n.start) > 0 {
-		e := &node{
-			start: n.start,
-			end:   span.Start,
-			ts:    n.ts,
+	seekRes := s.spanList.Seek(span.Start)
+
+	// if there is no change in the region span
+	// We just need to update the ts corresponding to the span in list
+	next := seekRes.Node().Next()
+	if next != nil {
+		cmpStart := bytes.Compare(seekRes.Node().Key(), span.Start)
+		cmpEnd := bytes.Compare(next.Key(), span.End)
+		if cmpStart == 0 && cmpEnd == 0 {
+			s.minTsHeap.UpdateKey(seekRes.Node().Value(), ts)
+			return
 		}
-		n.start = span.Start
-		s.list.insert(e)
-		s.minHeap.insert(e)
 	}
 
-	for n != nil {
-		oldTs := n.ts
-		if ts != n.ts {
-			s.minHeap.updateTs(n, ts)
-		}
-
-		next := n.next()
-		if next != nil && bytes.Compare(next.start, span.End) < 0 {
-			n = next
+	// regions are merged or split, overwrite span into list
+	node := seekRes.Node()
+	lastNodeTs := uint64(math.MaxUint64)
+	shouldInsertStartNode := true
+	if node.Value() != nil {
+		lastNodeTs = node.Value().key
+	}
+	for ; node != nil; node = node.Next() {
+		cmpStart := bytes.Compare(node.Key(), span.Start)
+		if cmpStart < 0 {
 			continue
 		}
-
-		// no more overlapped spans.
-		if cmp := bytes.Compare(span.End, n.end); cmp < 0 {
-			e := &node{
-				start: span.End,
-				end:   n.end,
-				ts:    oldTs,
-			}
-			s.list.insert(e)
-			n.end = span.End
-			s.minHeap.insert(e)
+		if bytes.Compare(node.Key(), span.End) > 0 {
+			break
+		}
+		lastNodeTs = node.Value().key
+		if cmpStart == 0 {
+			s.minTsHeap.UpdateKey(node.Value(), ts)
+			shouldInsertStartNode = false
+		} else {
+			s.spanList.Remove(seekRes, node)
+			s.minTsHeap.Remove(node.Value())
 		}
-		return
 	}
+	if shouldInsertStartNode {
+		s.spanList.InsertNextToNode(seekRes, span.Start, s.minTsHeap.Insert(ts))
+		seekRes.Next()
+	}
+	s.spanList.InsertNextToNode(seekRes, span.End, s.minTsHeap.Insert(lastNodeTs))
 }
 
 // Entries visit all traced spans.
-func (s *spanFrontier) Entries(fn func(start, end []byte, ts uint64)) {
-	for n := s.list.head.next(); n != nil; n = n.next() {
-		fn(n.start, n.end, n.ts)
-	}
+func (s *spanFrontier) Entries(fn func(key []byte, ts uint64)) {
+	s.spanList.Entries(func(n *skipListNode) bool {
+		fn(n.Key(), n.Value().key)
+		return true
+	})
 }
 
 func (s *spanFrontier) String() string {
 	var buf strings.Builder
-	for n := s.list.head.next(); n != nil; n = n.next() {
-		if buf.Len() != 0 {
-			buf.WriteString(` `)
+	s.Entries(func(key []byte, ts uint64) {
+		if ts == math.MaxUint64 {
+			buf.WriteString(fmt.Sprintf("[%s @ Max] ", key))
+		} else {
+			buf.WriteString(fmt.Sprintf("[%s @ %d] ", key, ts))
 		}
-		buf.WriteString(n.String())
-	}
+	})
 	return buf.String()
 }
diff --git a/cdc/puller/frontier/frontier_bench_test.go b/cdc/puller/frontier/frontier_bench_test.go
@@ -49,7 +49,7 @@ func BenchmarkSpanFrontier(b *testing.B) {
 				spans = append(spans, span)
 			}
 
-			f := NewFrontier(spans...)
+			f := NewFrontier(0, spans...)
 
 			b.ResetTimer()
 
@@ -91,7 +91,7 @@ func BenchmarkSpanFrontierOverlap(b *testing.B) {
 					})
 				}
 
-				f := NewFrontier(spans...)
+				f := NewFrontier(0, spans...)
 
 				b.ResetTimer()