diff --git a/README.md b/README.md
index 13a48c37..774db1cd 100644
--- a/README.md
+++ b/README.md
@@ -254,9 +254,9 @@ A bounding box consists of two points. The first being the southwestern most poi
 set fleet truck1 bounds 30 -110 40 -100
 ```
 #### Geohash
-A [geohash](https://en.wikipedia.org/wiki/Geohash) is a string respresentation of a point. With the length of the string indicating the precision of the point. 
+A [geohash](https://en.wikipedia.org/wiki/Geohash) is a string representation of a point. With the length of the string indicating the precision of the point. 
 ```
-set fleet truck1 hash 9tbnthxzr # this would be equivlent to 'point 33.5123 -112.2693'
+set fleet truck1 hash 9tbnthxzr # this would be equivalent to 'point 33.5123 -112.2693'
 ```
 
 #### GeoJSON
@@ -272,7 +272,7 @@ set city tempe object {"type":"Polygon","coordinates":[[[0,0],[10,10],[10,0],[0,
 
 #### XYZ Tile
 An XYZ tile is rectangle bounding area on earth that is represented by an X, Y coordinate and a Z (zoom) level.
-Check out [maptiler.org](https://www.maptiler.org/google-maps-coordinates-tile-bounds-projection/) for an interactive example.
+Check out [maptiler.org](http://www.maptiler.org/google-maps-coordinates-tile-bounds-projection/) for an interactive example.
 
 #### QuadKey
 A QuadKey used the same coordinate system as an XYZ tile except that the string representation is a string characters composed of 0, 1, 2, or 3. For a detailed explanation checkout [The Bing Maps Tile System](https://msdn.microsoft.com/en-us/library/bb259689.aspx).
diff --git a/internal/collection/collection.go b/internal/collection/collection.go
index 3f87fd8e..f9271579 100644
--- a/internal/collection/collection.go
+++ b/internal/collection/collection.go
@@ -1,6 +1,8 @@
 package collection
 
 import (
+	"runtime"
+
 	ifbtree "github.com/tidwall/btree"
 	"github.com/tidwall/geojson"
 	"github.com/tidwall/geojson/geo"
@@ -10,6 +12,9 @@ import (
 	"github.com/tidwall/tile38/internal/collection/rtree"
 )
 
+// yieldStep forces the iterator to yield goroutine every N steps.
+const yieldStep = 0xFF
+
 // Cursor allows for quickly paging through Scan, Within, Intersects, and Nearby
 type Cursor interface {
 	Offset() uint64
@@ -280,6 +285,9 @@ func (c *Collection) Scan(desc bool, cursor Cursor,
 		if count <= offset {
 			return true
 		}
+		if count&yieldStep == yieldStep {
+			runtime.Gosched()
+		}
 		if cursor != nil {
 			cursor.Step(1)
 		}
@@ -310,6 +318,9 @@ func (c *Collection) ScanRange(start, end string, desc bool, cursor Cursor,
 		if count <= offset {
 			return true
 		}
+		if count&yieldStep == yieldStep {
+			runtime.Gosched()
+		}
 		if cursor != nil {
 			cursor.Step(1)
 		}
@@ -350,6 +361,9 @@ func (c *Collection) SearchValues(desc bool, cursor Cursor,
 		if count <= offset {
 			return true
 		}
+		if count&yieldStep == yieldStep {
+			runtime.Gosched()
+		}
 		if cursor != nil {
 			cursor.Step(1)
 		}
@@ -382,6 +396,9 @@ func (c *Collection) SearchValuesRange(start, end string, desc bool,
 		if count <= offset {
 			return true
 		}
+		if count&yieldStep == yieldStep {
+			runtime.Gosched()
+		}
 		if cursor != nil {
 			cursor.Step(1)
 		}
@@ -422,6 +439,9 @@ func (c *Collection) ScanGreaterOrEqual(id string, desc bool,
 		if count <= offset {
 			return true
 		}
+		if count&yieldStep == yieldStep {
+			runtime.Gosched()
+		}
 		if cursor != nil {
 			cursor.Step(1)
 		}
@@ -544,6 +564,9 @@ func (c *Collection) Within(
 				if count <= offset {
 					return false, true
 				}
+				if count&yieldStep == yieldStep {
+					runtime.Gosched()
+				}
 				if cursor != nil {
 					cursor.Step(1)
 				}
@@ -560,6 +583,9 @@ func (c *Collection) Within(
 			if count <= offset {
 				return true
 			}
+			if count&yieldStep == yieldStep {
+				runtime.Gosched()
+			}
 			if cursor != nil {
 				cursor.Step(1)
 			}
@@ -594,6 +620,9 @@ func (c *Collection) Intersects(
 				if count <= offset {
 					return false, true
 				}
+				if count&yieldStep == yieldStep {
+					runtime.Gosched()
+				}
 				if cursor != nil {
 					cursor.Step(1)
 				}
@@ -610,6 +639,9 @@ func (c *Collection) Intersects(
 			if count <= offset {
 				return true
 			}
+			if count&yieldStep == yieldStep {
+				runtime.Gosched()
+			}
 			if cursor != nil {
 				cursor.Step(1)
 			}
@@ -667,6 +699,9 @@ func (c *Collection) Nearby(
 			if count <= offset {
 				return true
 			}
+			if count&yieldStep == yieldStep {
+				runtime.Gosched()
+			}
 			if cursor != nil {
 				cursor.Step(1)
 			}
diff --git a/internal/server/server.go b/internal/server/server.go
index d04fbc1c..6e7310c8 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -785,6 +785,7 @@ func (server *Server) watchLuaStatePool() {
 	}
 }
 
+// backgroundSyncAOF ensures that the aof buffer is does not grow too big.
 func (server *Server) backgroundSyncAOF() {
 	t := time.NewTicker(time.Second)
 	defer t.Stop()
@@ -792,12 +793,14 @@ func (server *Server) backgroundSyncAOF() {
 		if server.stopServer.on() {
 			return
 		}
-		server.mu.Lock()
-		if len(server.aofbuf) > 0 {
-			server.flushAOF(true)
-		}
-		server.aofbuf = nil
-		server.mu.Unlock()
+		func() {
+			server.mu.Lock()
+			defer server.mu.Unlock()
+			if len(server.aofbuf) > 0 {
+				server.flushAOF(true)
+			}
+			server.aofbuf = nil
+		}()
 	}
 }