From 2cba483d325debc5a023c204a29c746c71101c0b Mon Sep 17 00:00:00 2001
From: "Sascha L. Teichmann" <sascha.teichmann@intevation.de>
Date: Mon, 6 Mar 2017 11:44:06 +0100
Subject: [PATCH] redis client: Issue fewer write sys calls by fill hspatial
 request into a temp buffer first and write it in one go.

---
 common/redisclient.go | 35 +++++++++++++----------------------
 1 file changed, 13 insertions(+), 22 deletions(-)

diff --git a/common/redisclient.go b/common/redisclient.go
index 7a8e48e..23c04bb 100644
--- a/common/redisclient.go
+++ b/common/redisclient.go
@@ -18,7 +18,7 @@ type RedisClient struct {
 	conn    net.Conn
 	reader  *bufio.Reader
 	arena   []byte
-	scratch [80]byte
+	scratch [130]byte
 }
 
 func NewRedisClient(network, address string) (client *RedisClient, err error) {
@@ -42,34 +42,25 @@ var (
 	ignore      = []byte("IGNORE")
 )
 
-func (client *RedisClient) writeBulkString(buf []byte, data []byte) (err error) {
+func writeBulkString(buf []byte, data []byte) []byte {
 	buf = append(buf, '$')
 	buf = strconv.AppendInt(buf, int64(len(data)), 10)
 	buf = append(buf, nl...)
 	buf = append(buf, data...)
 	buf = append(buf, nl...)
-	_, err = client.conn.Write(buf)
-	return
+	return buf
 }
 
-func (client *RedisClient) writeHSpatial(p1, p2 int64) (err error) {
-	if _, err = client.conn.Write(writeArray4); err != nil {
-		return
-	}
-	b1 := client.scratch[:0:40]
-	b2 := client.scratch[40:40:80]
-
-	if err = client.writeBulkString(b1, hspatial); err != nil {
-		return
-	}
-	if err = client.writeBulkString(b1, ignore); err != nil {
-		return
-	}
-	if err = client.writeBulkString(b1, keyToBytes(p1, b2)); err != nil {
-		return
-	}
-	err = client.writeBulkString(b1, keyToBytes(p2, b2))
-	return
+func (client *RedisClient) writeHSpatial(p1, p2 int64) error {
+	tmp := client.scratch[:0:40]
+	buf := client.scratch[40:40]
+	buf = append(buf, writeArray4...)
+	buf = writeBulkString(buf, hspatial)
+	buf = writeBulkString(buf, ignore)
+	buf = writeBulkString(buf, keyToBytes(p1, tmp))
+	buf = writeBulkString(buf, keyToBytes(p2, tmp))
+	_, err := client.conn.Write(buf)
+	return err
 }
 
 func isError(line []byte) error {