diff --git a/src/observer/mysql/obmp_packet_sender.cpp b/src/observer/mysql/obmp_packet_sender.cpp
index e8ac65c67..99210ac06 100644
--- a/src/observer/mysql/obmp_packet_sender.cpp
+++ b/src/observer/mysql/obmp_packet_sender.cpp
@@ -1026,9 +1026,9 @@ bool ObMPPacketSender::has_pl()
   return has_pl;
 }
 
-// current lob will <= 64MB, TODO oushen
+// current max_allow_packet_size <= 1G, TODO haozheng
 int64_t ObMPPacketSender::TRY_EZ_BUF_SIZES[] = {64*1024, 128*1024, 2*1024*1024 - 1024, 4*1024*1024 - 1024,
-                                                64*1024*1024 - 1024, 128*1024*1024};
+                                                64*1024*1024 - 1024, 128*1024*1024, 512*1024*1024, 1024*1024*1024};
 
 
 }; // end namespace observer
diff --git a/src/observer/mysql/obmp_packet_sender.h b/src/observer/mysql/obmp_packet_sender.h
index e31c36e0b..ba06b9e7d 100644
--- a/src/observer/mysql/obmp_packet_sender.h
+++ b/src/observer/mysql/obmp_packet_sender.h
@@ -155,7 +155,7 @@ public:
   bool has_pl();
 
 private:
-  static const int64_t MAX_TRY_STEPS = 6;
+  static const int64_t MAX_TRY_STEPS = 8;
   static int64_t TRY_EZ_BUF_SIZES[MAX_TRY_STEPS];
 
   int alloc_ezbuf();