From ce7283ae1b180452558bd5563e6c7aef52b1a4bd Mon Sep 17 00:00:00 2001
From: Matthew Jaffee <jaffee@pilosa.com>
Date: Tue, 19 Sep 2017 15:52:42 -0500
Subject: [PATCH] convert to RWMutex in index, holder, view, and frame

use RLock and RUnlock in mapperLocal hotpath
---
 frame.go  | 10 +++++-----
 holder.go |  6 +++---
 index.go  |  6 +++---
 view.go   |  6 +++---
 4 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/frame.go b/frame.go
index f9580cc6b..2fcb0c47d 100644
--- a/frame.go
+++ b/frame.go
@@ -43,7 +43,7 @@ const (
 
 // Frame represents a container for views.
 type Frame struct {
-	mu          sync.Mutex
+	mu          sync.RWMutex
 	path        string
 	index       string
 	name        string
@@ -404,8 +404,8 @@ func (f *Frame) Close() error {
 
 // Schema returns the frame's current schema.
 func (f *Frame) Schema() *FrameSchema {
-	f.mu.Lock()
-	defer f.mu.Unlock()
+	f.mu.RLock()
+	defer f.mu.RUnlock()
 	return f.schema
 }
 
@@ -506,8 +506,8 @@ func (f *Frame) ViewPath(name string) string {
 
 // View returns a view in the frame by name.
 func (f *Frame) View(name string) *View {
-	f.mu.Lock()
-	defer f.mu.Unlock()
+	f.mu.RLock()
+	defer f.mu.RUnlock()
 	return f.view(name)
 }
 
diff --git a/holder.go b/holder.go
index 4270c2594..0cf5f6901 100644
--- a/holder.go
+++ b/holder.go
@@ -38,7 +38,7 @@ const (
 
 // Holder represents a container for indexes.
 type Holder struct {
-	mu sync.Mutex
+	mu sync.RWMutex
 
 	// Indexes by name.
 	indexes map[string]*Index
@@ -183,8 +183,8 @@ func (h *Holder) IndexPath(name string) string { return filepath.Join(h.Path, na
 
 // Index returns the index by name.
 func (h *Holder) Index(name string) *Index {
-	h.mu.Lock()
-	defer h.mu.Unlock()
+	h.mu.RLock()
+	defer h.mu.RUnlock()
 	return h.index(name)
 }
 
diff --git a/index.go b/index.go
index 345215690..5c7e06f05 100644
--- a/index.go
+++ b/index.go
@@ -37,7 +37,7 @@ const (
 
 // Index represents a container for frames.
 type Index struct {
-	mu   sync.Mutex
+	mu   sync.RWMutex
 	path string
 	name string
 
@@ -345,8 +345,8 @@ func (i *Index) InputDefinitionPath() string {
 
 // Frame returns a frame in the index by name.
 func (i *Index) Frame(name string) *Frame {
-	i.mu.Lock()
-	defer i.mu.Unlock()
+	i.mu.RLock()
+	defer i.mu.RUnlock()
 	return i.frame(name)
 }
 
diff --git a/view.go b/view.go
index 2d5b7d776..3f5a61437 100644
--- a/view.go
+++ b/view.go
@@ -43,7 +43,7 @@ func IsValidView(name string) bool {
 
 // View represents a container for frame data.
 type View struct {
-	mu    sync.Mutex
+	mu    sync.RWMutex
 	path  string
 	index string
 	frame string
@@ -194,8 +194,8 @@ func (v *View) FragmentPath(slice uint64) string {
 
 // Fragment returns a fragment in the view by slice.
 func (v *View) Fragment(slice uint64) *Fragment {
-	v.mu.Lock()
-	defer v.mu.Unlock()
+	v.mu.RLock()
+	defer v.mu.RUnlock()
 	return v.fragment(slice)
 }