diff --git a/config/config.go b/config/config.go
index 3f391902464bd..603ac291099a0 100644
--- a/config/config.go
+++ b/config/config.go
@@ -39,7 +39,7 @@ import (
 const (
 	MaxLogFileSize = 4096 // MB
 	// DefTxnTotalSizeLimit is the default value of TxnTxnTotalSizeLimit.
-	DefTxnTotalSizeLimit = 1024 * 1024 * 1024
+	DefTxnTotalSizeLimit = 100 * 1024 * 1024
 )
 
 // Valid config maps
diff --git a/config/config.toml.example b/config/config.toml.example
index 4bc5f98618165..3c5c567747a5f 100644
--- a/config/config.toml.example
+++ b/config/config.toml.example
@@ -215,9 +215,9 @@ bind-info-lease = "3s"
 
 # The limitation of the size in byte for the entries in one transaction.
 # If using TiKV as the storage, the entry represents a key/value pair.
-# WARNING: Do not set the value too large, otherwise it will make a very large impact on the TiKV cluster.
-# Please adjust this configuration carefully.
-txn-total-size-limit = 1073741824
+# NOTE: If binlog is enabled, this value should be less than 104857600(10M) because this is the maximum size that can be handled by Pumper.
+# If binlog is not enabled, this value should be less than 10737418240(10G).
+txn-total-size-limit = 104857600
 
 [proxy-protocol]
 # PROXY protocol acceptable client networks.
@@ -327,6 +327,7 @@ capacity = 2048000
 
 [binlog]
 # enable to write binlog.
+# NOTE: If binlog is enabled, txn-total-size-limit should be less than 104857600(10M).
 enable = false
 
 # WriteTimeout specifies how long it will wait for writing binlog to pump.