diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/metrics/EventChannel.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/metrics/EventChannel.java
index 83e844a0b1..8c998ed562 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/metrics/EventChannel.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/metrics/EventChannel.java
@@ -71,10 +71,7 @@ public class EventChannel {
         public void run() {
             while (!isStop.get() || !queue.isEmpty()) {
                 try {
-                    Event e = queue.poll();
-                    if (e == null) {
-                        continue;
-                    }
+                    Event e = queue.take();
                     for (EventConsumer consumer : consumers.get(e.getClass())) {
                         if (enhancers.containsKey(e.getClass())) {
                             enhancers.get(e.getClass()).enhance(e);
@@ -115,14 +112,5 @@ public class EventChannel {
      */
     public void stop() {
         isStop.set(true);
-        if (thread != null) {
-            try {
-                thread.join();
-            } catch (InterruptedException e) {
-                LOG.warn("join worker failed.", e);
-            } finally {
-                thread = null;
-            }
-        }
     }
 }
diff --git a/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java b/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java
index 214f983c8b..090af9f695 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java
@@ -144,7 +144,7 @@ public class VariableMgr {
         if (!attr.checker().equals("")) {
             Preconditions.checkArgument(obj instanceof SessionVariable);
             try {
-                SessionVariable.class.getDeclaredMethod(attr.checker()).invoke(obj);
+                SessionVariable.class.getDeclaredMethod(attr.checker(), String.class).invoke(obj, value);
             } catch (Exception e) {
                 ErrorReport.reportDdlException(ErrorCode.ERR_INVALID_VALUE, attr.name(), value, e.getMessage());
             }
@@ -527,6 +527,7 @@ public class VariableMgr {
 
         // the function name that check the VarAttr before setting it to sessionVariable
         // only support check function: 0 argument and 0 return value, if an error occurs, throw an exception.
+        // the checker function should be: public void checker(String value), value is the input string.
         String checker() default "";
 
         // Set to true if the variables need to be forwarded along with forward statement.