diff --git a/pom.xml b/pom.xml
index de99f05e..49214b9c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,18 +4,10 @@
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
-    <properties>
-        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <vertxVersion>4.5.4</vertxVersion>
-        <commonmarkVersion>0.21.0</commonmarkVersion>
-        <jacksonVersion>2.15.3</jacksonVersion>
-        <poiVersion>5.2.5</poiVersion>
-    </properties>
-
     <groupId>io.github.sinri</groupId>
     <artifactId>Keel</artifactId>
-    <!--    <version>3.2.3-SNAPSHOT</version>-->
-    <version>3.2.3</version>
+    <version>3.2.4-SNAPSHOT</version>
+    <!--    <version>3.2.3</version>-->
 
     <name>Keel</name>
     <description>
@@ -44,6 +36,14 @@
         </developer>
     </developers>
 
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <vertxVersion>4.5.4</vertxVersion>
+        <commonmarkVersion>0.21.0</commonmarkVersion>
+        <jacksonVersion>2.15.3</jacksonVersion>
+        <poiVersion>5.2.5</poiVersion>
+    </properties>
+
     <dependencies>
         <dependency>
             <groupId>io.vertx</groupId>
diff --git a/src/main/java/io/github/sinri/keel/core/KeelCronExpression.java b/src/main/java/io/github/sinri/keel/core/KeelCronExpression.java
index 4d9d86cd..a866978c 100644
--- a/src/main/java/io/github/sinri/keel/core/KeelCronExpression.java
+++ b/src/main/java/io/github/sinri/keel/core/KeelCronExpression.java
@@ -1,5 +1,7 @@
 package io.github.sinri.keel.core;
 
+
+import javax.annotation.Nonnull;
 import java.util.*;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -13,9 +15,9 @@ public class KeelCronExpression {
     final Set<Integer> dayOptions = new HashSet<>();
     final Set<Integer> monthOptions = new HashSet<>();
     final Set<Integer> weekdayOptions = new HashSet<>();
-    private final String rawCronExpression;
+    private final @Nonnull String rawCronExpression;
 
-    public KeelCronExpression(String rawCronExpression) {
+    public KeelCronExpression(@Nonnull String rawCronExpression) {
         this.rawCronExpression = rawCronExpression;
 
         String[] parts = rawCronExpression.trim().split("\\s+");
@@ -36,24 +38,20 @@ public KeelCronExpression(String rawCronExpression) {
         parseField(weekdayExpression, weekdayOptions, 0, 6);
     }
 
-    public boolean match(Calendar currentCalendar) {
-        // currentCalendar := Calendar.getInstance();
-        int minute = currentCalendar.get(Calendar.MINUTE);
-        int hour = currentCalendar.get(Calendar.HOUR_OF_DAY);
-        int day = currentCalendar.get(Calendar.DAY_OF_MONTH);
-        int month = 1 + currentCalendar.get(Calendar.MONTH);// make JAN 1, ...
-        int weekday = currentCalendar.get(Calendar.DAY_OF_WEEK) - 1; // make sunday 0, ...
-
-        return minuteOptions.contains(minute)
-                && hourOptions.contains(hour)
-                && dayOptions.contains(day)
-                && monthOptions.contains(month)
-                && weekdayOptions.contains(weekday);
+    public boolean match(@Nonnull Calendar currentCalendar) {
+        ParsedCalenderElements parsedCalenderElements = new ParsedCalenderElements(currentCalendar);
+        return match(parsedCalenderElements);
     }
 
-    private void parseField(String rawComponent, Set<Integer> optionSet, int min, int max) {
-//        System.out.println("parseField: " + rawComponent);
+    public boolean match(@Nonnull ParsedCalenderElements parsedCalenderElements) {
+        return minuteOptions.contains(parsedCalenderElements.minute)
+                && hourOptions.contains(parsedCalenderElements.hour)
+                && dayOptions.contains(parsedCalenderElements.day)
+                && monthOptions.contains(parsedCalenderElements.month)
+                && weekdayOptions.contains(parsedCalenderElements.weekday);
+    }
 
+    private void parseField(@Nonnull String rawComponent, @Nonnull Set<Integer> optionSet, int min, int max) {
         if (rawComponent.equals("*")) {
             for (int i = min; i <= max; i++) {
                 optionSet.add(i);
@@ -106,10 +104,35 @@ private void parseField(String rawComponent, Set<Integer> optionSet, int min, in
         }
     }
 
+    @Nonnull
     public String getRawCronExpression() {
         return rawCronExpression;
     }
 
+    /**
+     * @since 3.2.4
+     */
+    public static class ParsedCalenderElements {
+        public final int minute;
+        public final int hour;
+        public final int day;
+        public final int month;
+        public final int weekday;
+
+        public ParsedCalenderElements(@Nonnull Calendar currentCalendar) {
+            minute = currentCalendar.get(Calendar.MINUTE);
+            hour = currentCalendar.get(Calendar.HOUR_OF_DAY);
+            day = currentCalendar.get(Calendar.DAY_OF_MONTH);
+            month = 1 + currentCalendar.get(Calendar.MONTH);// make JAN 1, ...
+            weekday = currentCalendar.get(Calendar.DAY_OF_WEEK) - 1; // make sunday 0, ...
+        }
+
+        @Override
+        public String toString() {
+            return minute + " " + hour + " " + day + " " + month + " " + weekday;
+        }
+    }
+
     @Override
     public String toString() {
         return getRawCronExpression();
diff --git a/src/main/java/io/github/sinri/keel/facade/KeelInstance.java b/src/main/java/io/github/sinri/keel/facade/KeelInstance.java
index 6a51217e..f89314b1 100644
--- a/src/main/java/io/github/sinri/keel/facade/KeelInstance.java
+++ b/src/main/java/io/github/sinri/keel/facade/KeelInstance.java
@@ -6,7 +6,10 @@
 import io.github.sinri.keel.logger.KeelLogLevel;
 import io.github.sinri.keel.logger.event.KeelEventLogger;
 import io.github.sinri.keel.logger.issue.center.KeelIssueRecordCenter;
-import io.vertx.core.*;
+import io.vertx.core.Future;
+import io.vertx.core.Promise;
+import io.vertx.core.Vertx;
+import io.vertx.core.VertxOptions;
 import io.vertx.core.spi.cluster.ClusterManager;
 
 import javax.annotation.Nonnull;
@@ -130,7 +133,7 @@ public KeelInstance setLogger(@Nonnull KeelEventLogger eventLogger) {
         return this;
     }
 
-    public Future<Void> gracefullyClose(@Nonnull Handler<Promise<Void>> promiseHandler) {
+    public Future<Void> gracefullyClose(@Nonnull io.vertx.core.Handler<Promise<Void>> promiseHandler) {
         Promise<Void> promise = Promise.promise();
         promiseHandler.handle(promise);
         return promise.future().compose(v -> getVertx().close());
diff --git a/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundial.java b/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundial.java
index d814e931..592fc65f 100644
--- a/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundial.java
+++ b/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundial.java
@@ -1,19 +1,22 @@
 package io.github.sinri.keel.servant.sundial;
 
+import io.github.sinri.keel.core.KeelCronExpression;
+import io.github.sinri.keel.facade.async.KeelAsyncKit;
 import io.github.sinri.keel.logger.event.KeelEventLogger;
 import io.github.sinri.keel.logger.issue.center.KeelIssueRecordCenter;
 import io.github.sinri.keel.verticles.KeelVerticleImplWithEventLogger;
 import io.vertx.core.Future;
+import io.vertx.core.json.JsonObject;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicInteger;
-import java.util.function.Supplier;
 
 import static io.github.sinri.keel.facade.KeelInstance.Keel;
 
 /**
  * @since 3.0.0
+ * @since 3.2.4 use verticle to handle the sundial plan executing.
  */
 public abstract class KeelSundial extends KeelVerticleImplWithEventLogger {
     private final Map<String, KeelSundialPlan> planMap = new ConcurrentHashMap<>();
@@ -33,47 +36,55 @@ public void start() throws Exception {
         this.timerID = Keel.getVertx().setPeriodic(delaySeconds, 60_000L, timerID -> {
             Calendar calendar = Calendar.getInstance();
             handleEveryMinute(calendar);
+            refreshPlans();
         });
     }
 
     private void handleEveryMinute(Calendar now) {
+        KeelCronExpression.ParsedCalenderElements parsedCalenderElements = new KeelCronExpression.ParsedCalenderElements(now);
         planMap.forEach((key, plan) -> {
-            if (plan.cronExpression().match(now)) {
+            if (plan.cronExpression().match(parsedCalenderElements)) {
+                getLogger().debug("Sundial Plan Matched", new JsonObject()
+                        .put("plan_key", plan.key())
+                        .put("plan_cron", plan.cronExpression())
+                        .put("now", parsedCalenderElements.toString())
+                );
                 plan.execute(now);
+            } else {
+                getLogger().debug("Sundial Plan Not Match", new JsonObject()
+                        .put("plan_key", plan.key())
+                        .put("plan_cron", plan.cronExpression())
+                        .put("now", parsedCalenderElements.toString())
+                );
             }
         });
-
-        // refresh plan, pfs {0: not-fetching, more: fetching}
-        if (planFetchingSemaphore.get() == 0) {
-            planFetchingSemaphore.incrementAndGet();
-            fetchPlans()
-                    .compose(plans -> {
-                        if (plans == null) {
-                            // treat null as NOT MODIFIED
-                            return Future.succeededFuture();
-                        }
-                        Set<String> toDelete = new HashSet<>(planMap.keySet());
-                        plans.forEach(plan -> {
-                            toDelete.remove(plan.key());
-                            planMap.put(plan.key(), plan);
-                        });
-                        if (!toDelete.isEmpty()) {
-                            toDelete.forEach(planMap::remove);
-                        }
-                        return Future.succeededFuture();
-                    })
-                    .eventually(() -> {
-                        planFetchingSemaphore.decrementAndGet();
-                        return Future.succeededFuture();
-                    });
-
-        }
-
     }
 
-    @Deprecated(since = "3.0.1", forRemoval = true)
-    protected Supplier<Collection<KeelSundialPlan>> plansSupplier() {
-        return null;
+    /**
+     * @since 3.2.4
+     */
+    private void refreshPlans() {
+        KeelAsyncKit.exclusivelyCall(
+                "io.github.sinri.keel.servant.sundial.KeelSundial.refreshPlans",
+                1000L,
+                () -> {
+                    return fetchPlans()
+                            .compose(plans -> {
+                                // treat null as NOT MODIFIED
+                                if (plans != null) {
+                                    Set<String> toDelete = new HashSet<>(planMap.keySet());
+                                    plans.forEach(plan -> {
+                                        toDelete.remove(plan.key());
+                                        planMap.put(plan.key(), plan);
+                                    });
+                                    if (!toDelete.isEmpty()) {
+                                        toDelete.forEach(planMap::remove);
+                                    }
+                                }
+                                return Future.succeededFuture();
+                            });
+                }
+        );
     }
 
     /**
diff --git a/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundialPlan.java b/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundialPlan.java
index 50f52b51..37812b2f 100644
--- a/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundialPlan.java
+++ b/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundialPlan.java
@@ -1,16 +1,18 @@
 package io.github.sinri.keel.servant.sundial;
 
 import io.github.sinri.keel.core.KeelCronExpression;
+import io.vertx.core.Future;
 
 import java.util.Calendar;
 
 /**
  * @since 3.0.0
+ * @since 3.2.4 change sync method `execute` to be async.
  */
 public interface KeelSundialPlan {
     String key();
 
     KeelCronExpression cronExpression();
 
-    void execute(Calendar now);
+    Future<Void> execute(Calendar now);
 }
diff --git a/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundialVerticle.java b/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundialVerticle.java
new file mode 100644
index 00000000..c5129046
--- /dev/null
+++ b/src/main/java/io/github/sinri/keel/servant/sundial/KeelSundialVerticle.java
@@ -0,0 +1,31 @@
+package io.github.sinri.keel.servant.sundial;
+
+import io.github.sinri.keel.verticles.KeelVerticleImplPure;
+import io.vertx.core.Future;
+
+import javax.annotation.Nonnull;
+import java.util.Calendar;
+
+/**
+ * @since 3.2.4
+ */
+public class KeelSundialVerticle extends KeelVerticleImplPure {
+    private final KeelSundialPlan sundialPlan;
+    private final Calendar now;
+
+    public KeelSundialVerticle(@Nonnull KeelSundialPlan sundialPlan, Calendar now) {
+        this.sundialPlan = sundialPlan;
+        this.now = now;
+    }
+
+    @Override
+    public void start() throws Exception {
+        Future.succeededFuture()
+                .compose(v -> {
+                    return sundialPlan.execute(now);
+                })
+                .onComplete(ar -> {
+                    undeployMe();
+                });
+    }
+}