From 40181c10421d0a2f316e7b27a8b00dd2d1985981 Mon Sep 17 00:00:00 2001
From: huija <1150555483@qq.com>
Date: Fri, 19 Jun 2020 14:21:12 +0800
Subject: [PATCH 1/3] Update redis.go

use `scan` instead of `keys`
---
 cache/redis/redis.go | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/cache/redis/redis.go b/cache/redis/redis.go
index 372dd48b..e70c745b 100644
--- a/cache/redis/redis.go
+++ b/cache/redis/redis.go
@@ -139,7 +139,7 @@ func (rc *Cache) Decr(key string) error {
 func (rc *Cache) ClearAll() error {
 	c := rc.p.Get()
 	defer c.Close()
-	cachedKeys, err := redis.Strings(c.Do("KEYS", rc.key+":*"))
+	cachedKeys, err := rc.Scan(rc.key + ":*")
 	if err != nil {
 		return err
 	}
@@ -151,6 +151,34 @@ func (rc *Cache) ClearAll() error {
 	return err
 }
 
+func (rc *Cache) Scan(pattern string) (keys []string, err error) {
+	c := rc.p.Get()
+	defer c.Close()
+	var (
+		cursor uint64 = 0 // start
+		result []interface{}
+		list   []string
+	)
+	for {
+		result, err = redis.Values(c.Do("SCAN", cursor, "MATCH", pattern, "COUNT", 1024))
+		if err != nil {
+			return
+		}
+		list, err = redis.Strings(result[1], nil)
+		if err != nil {
+			return
+		}
+		keys = append(keys, list...)
+		cursor, err = redis.Uint64(result[0], nil)
+		if err != nil {
+			return
+		}
+		if cursor == 0 { // over
+			return
+		}
+	}
+}
+
 // StartAndGC start redis cache adapter.
 // config is like {"key":"collection key","conn":"connection info","dbNum":"0"}
 // the cache item in redis are stored forever,

From f2bae3e367aaeae22588789bde32f1631d0b8303 Mon Sep 17 00:00:00 2001
From: huija <1150555483@qq.com>
Date: Fri, 19 Jun 2020 22:55:40 +0800
Subject: [PATCH 2/3] add UT for Scan function

---
 cache/redis/redis.go      |  4 ++--
 cache/redis/redis_test.go | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/cache/redis/redis.go b/cache/redis/redis.go
index e70c745b..a1ea7b49 100644
--- a/cache/redis/redis.go
+++ b/cache/redis/redis.go
@@ -137,12 +137,12 @@ func (rc *Cache) Decr(key string) error {
 
 // ClearAll clean all cache in redis. delete this redis collection.
 func (rc *Cache) ClearAll() error {
-	c := rc.p.Get()
-	defer c.Close()
 	cachedKeys, err := rc.Scan(rc.key + ":*")
 	if err != nil {
 		return err
 	}
+	c := rc.p.Get()
+	defer c.Close()
 	for _, str := range cachedKeys {
 		if _, err = c.Do("DEL", str); err != nil {
 			return err
diff --git a/cache/redis/redis_test.go b/cache/redis/redis_test.go
index 56877f6b..7ac88f87 100644
--- a/cache/redis/redis_test.go
+++ b/cache/redis/redis_test.go
@@ -15,6 +15,7 @@
 package redis
 
 import (
+	"fmt"
 	"testing"
 	"time"
 
@@ -104,3 +105,40 @@ func TestRedisCache(t *testing.T) {
 		t.Error("clear all err")
 	}
 }
+
+func TestCache_Scan(t *testing.T) {
+	timeoutDuration := 10 * time.Second
+	// init
+	bm, err := cache.NewCache("redis", `{"conn": "127.0.0.1:6379"}`)
+	if err != nil {
+		t.Error("init err")
+	}
+	// insert all
+	for i := 0; i < 10000; i++ {
+		if err = bm.Put(fmt.Sprintf("astaxie%d", i), fmt.Sprintf("author%d", i), timeoutDuration); err != nil {
+			t.Error("set Error", err)
+		}
+	}
+	// scan all for the first time
+	keys, err := bm.(*Cache).Scan(DefaultKey + ":*")
+	if err != nil {
+		t.Error("scan Error", err)
+	}
+	if len(keys) != 10000 {
+		t.Error("scan all err")
+	}
+
+	// clear all
+	if err = bm.ClearAll(); err != nil {
+		t.Error("clear all err")
+	}
+
+	// scan all for the second time
+	keys, err = bm.(*Cache).Scan(DefaultKey + ":*")
+	if err != nil {
+		t.Error("scan Error", err)
+	}
+	if len(keys) != 0 {
+		t.Error("scan all err")
+	}
+}

From f70fd5babfcb206fb5aab3d2e771052345337a7b Mon Sep 17 00:00:00 2001
From: huija <1150555483@qq.com>
Date: Tue, 23 Jun 2020 12:32:26 +0800
Subject: [PATCH 3/3] add comments on Scan func

---
 cache/redis/redis.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cache/redis/redis.go b/cache/redis/redis.go
index a1ea7b49..7a14b012 100644
--- a/cache/redis/redis.go
+++ b/cache/redis/redis.go
@@ -151,6 +151,7 @@ func (rc *Cache) ClearAll() error {
 	return err
 }
 
+// Scan scan all keys matching the pattern. a better choice than `keys`
 func (rc *Cache) Scan(pattern string) (keys []string, err error) {
 	c := rc.p.Get()
 	defer c.Close()