From fabf30d8f4a86856388c018d986bd05a80282365 Mon Sep 17 00:00:00 2001
From: djshow832 <873581766@qq.com>
Date: Mon, 5 Sep 2022 12:06:25 +0800
Subject: [PATCH 1/2] make channel size 1

---
 pkg/proxy/backend/backend_conn_mgr.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkg/proxy/backend/backend_conn_mgr.go b/pkg/proxy/backend/backend_conn_mgr.go
index aeb63e2a..3b815764 100644
--- a/pkg/proxy/backend/backend_conn_mgr.go
+++ b/pkg/proxy/backend/backend_conn_mgr.go
@@ -88,7 +88,7 @@ func NewBackendConnManager(connectionID uint64) *BackendConnManager {
 		connectionID:   connectionID,
 		cmdProcessor:   NewCmdProcessor(),
 		authenticator:  &Authenticator{},
-		signalReceived: make(chan struct{}),
+		signalReceived: make(chan struct{}, 1),
 		redirectResCh:  make(chan *redirectResult, 1),
 	}
 }

From c2416ed0e6aa71880977da60d3a1bb14fbe409f1 Mon Sep 17 00:00:00 2001
From: djshow832 <873581766@qq.com>
Date: Mon, 5 Sep 2022 12:27:41 +0800
Subject: [PATCH 2/2] wait for the channel

---
 pkg/proxy/backend/backend_conn_mgr.go | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/pkg/proxy/backend/backend_conn_mgr.go b/pkg/proxy/backend/backend_conn_mgr.go
index 3b815764..158da8f9 100644
--- a/pkg/proxy/backend/backend_conn_mgr.go
+++ b/pkg/proxy/backend/backend_conn_mgr.go
@@ -292,10 +292,8 @@ func (mgr *BackendConnManager) Redirect(newAddr string) {
 	atomic.StorePointer(&mgr.signal, unsafe.Pointer(&signalRedirect{
 		newAddr: newAddr,
 	}))
-	select {
-	case mgr.signalReceived <- struct{}{}:
-	default:
-	}
+	// Generally, it won't wait because the caller won't send another signal because the last one finishes.
+	mgr.signalReceived <- struct{}{}
 }
 
 // GetRedirectingAddr implements RedirectableConn.GetRedirectingAddr interface.