From 9eb4ada1c7ec0934941d45f2dd4a2f21dae06199 Mon Sep 17 00:00:00 2001
From: zhangkun <>
Date: Thu, 10 Feb 2022 19:37:20 +0800
Subject: [PATCH] avoid cache avalanche

At the beginning of client start, there is no table region info in cache.
If there are many go routine to access a table at same time, they will miss cache and send request package to get table region info.
In this case, too many duplicated requests should be avoid.
---
 client.go |  4 ++++
 rpc.go    | 12 ++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/client.go b/client.go
index 982ddb27..52adf57b 100644
--- a/client.go
+++ b/client.go
@@ -97,6 +97,10 @@ type client struct {
 		string, time.Duration, compression.Codec) hrpc.RegionClient
 
 	compressionCodec compression.Codec
+
+
+	// region looker lock container
+	regionLookerMap sync.Map
 }
 
 // NewClient creates a new HBase client.
diff --git a/rpc.go b/rpc.go
index 32875ac1..d7f2e9ee 100644
--- a/rpc.go
+++ b/rpc.go
@@ -12,6 +12,7 @@ import (
 	"fmt"
 	"io"
 	"strconv"
+	"sync"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -54,6 +55,17 @@ const (
 )
 
 func (c *client) getRegionForRpc(rpc hrpc.Call) (hrpc.RegionInfo, error) {
+	// Check the cache for a region that can handle this request
+	// if in cache, return quickly
+	if reg := c.getRegionFromCache(rpc.Table(), rpc.Key()); reg != nil {
+		return reg, nil
+	}
+
+	il, _ := c.regionLookerMap.LoadOrStore(string(rpc.Table()), &sync.Mutex{})
+	lo := il.(*sync.Mutex)
+	lo.Lock()
+	defer lo.Unlock()
+
 	for i := 0; i < maxFindRegionTries; i++ {
 		// Check the cache for a region that can handle this request
 		if reg := c.getRegionFromCache(rpc.Table(), rpc.Key()); reg != nil {