Merge pull request #1365 from tgruben/slicecount-optimization

WIP count optimization

enterprise/b/containers_btree.go

@@ -121,6 +121,16 @@ func (btc *BTreeContainers) GetOrCreate(key uint64) *roaring.Container {
 	return btc.lastContainer
 }
 
+func (btc *BTreeContainers) Count() (n uint64) {
+	e, _ := btc.tree.Seek(0)
+	_, c, err := e.Next()
+	for err != io.EOF {
+		n += uint64(c.N())
+		_, c, err = e.Next()
+	}
+	return
+}
+
 func (btc *BTreeContainers) Clone() roaring.Containers {
 	nbtc := NewBTreeContainers()
 

roaring/containers.go

@@ -124,6 +124,14 @@ func (sc *SliceContainers) Size() int {
 
 }
 
+func (sc *SliceContainers) Count() uint64 {
+	n := uint64(0)
+	for i := range sc.containers {
+		n += uint64(sc.containers[i].n)
+	}
+	return n
+}
+
 func (sc *SliceContainers) seek(key uint64) (int, bool) {
 	i := search64(sc.keys, key)
 	found := true
@@ -153,6 +161,7 @@ func (si *SliceIterator) Next() bool {
 	si.key = si.e.keys[si.i]
 	si.value = si.e.containers[si.i]
 	si.i++
+
 	return true
 }
 

roaring/roaring.go

@@ -93,6 +93,7 @@ type Containers interface {
 	// return the first container at or after key. found will be true if a
 	// container is found at key.
 	Iterator(key uint64) (citer ContainerIterator, found bool)
+	Count() uint64
 }
 
 type ContainerIterator interface {
@@ -218,12 +219,7 @@ func (b *Bitmap) Max() uint64 {
 
 // Count returns the number of bits set in the bitmap.
 func (b *Bitmap) Count() (n uint64) {
-	citer, _ := b.Containers.Iterator(0)
-	for citer.Next() {
-		_, c := citer.Value()
-		n += uint64(c.n)
-	}
-	return n
+	return b.Containers.Count()
 }
 
 // CountRange returns the number of bits set between [start, end).
@@ -1030,6 +1026,11 @@ func (c *Container) Mapped() bool {
 	return c.mapped
 }
 
+// N returns the cached bit count of the container
+func (c *Container) N() int {
+	return c.n
+}
+
 // Update updates the container
 func (c *Container) Update(containerType byte, n int, mapped bool) {
 	c.containerType = containerType