diff --git a/s3stream/src/main/java/com/automq/stream/s3/wal/SlidingWindowService.java b/s3stream/src/main/java/com/automq/stream/s3/wal/SlidingWindowService.java
index cc6f94a0d..657615310 100644
--- a/s3stream/src/main/java/com/automq/stream/s3/wal/SlidingWindowService.java
+++ b/s3stream/src/main/java/com/automq/stream/s3/wal/SlidingWindowService.java
@@ -94,7 +94,14 @@ public class SlidingWindowService {
      */
     private Block currentBlock;
 
+    /**
+     * The thread pool for write operations.
+     */
     private ExecutorService ioExecutor;
+    /**
+     * The scheduler for polling blocks and sending them to @{@link #ioExecutor}.
+     */
+    private ScheduledExecutorService pollBlockScheduler;
 
     /**
      * The last time when a batch of blocks is written to the disk.
@@ -121,7 +128,7 @@ public void start(AtomicLong windowMaxLength, long windowStartOffset) {
         this.windowCoreData = new WindowCoreData(windowMaxLength, windowStartOffset, windowStartOffset);
         this.ioExecutor = Threads.newFixedThreadPoolWithMonitor(ioThreadNums,
             "block-wal-io-thread", false, LOGGER);
-        ScheduledExecutorService pollBlockScheduler = Threads.newSingleThreadScheduledExecutor(
+        this.pollBlockScheduler = Threads.newSingleThreadScheduledExecutor(
             ThreadUtils.createThreadFactory("wal-poll-block-thread-%d", false), LOGGER);
         pollBlockScheduler.scheduleAtFixedRate(this::tryWriteBlock, 0, minWriteIntervalNanos, TimeUnit.NANOSECONDS);
         initialized.set(true);
@@ -138,6 +145,7 @@ public boolean shutdown(long timeout, TimeUnit unit) {
 
         boolean gracefulShutdown;
         this.ioExecutor.shutdown();
+        this.pollBlockScheduler.shutdownNow();
         try {
             gracefulShutdown = this.ioExecutor.awaitTermination(timeout, unit);
         } catch (InterruptedException e) {
@@ -348,25 +356,15 @@ private void writeBlockData(BlockBatch blocks) throws IOException {
         S3StreamMetricsManager.recordStageLatency(MetricsLevel.DEBUG, timer.elapsedAs(TimeUnit.NANOSECONDS), S3Stage.APPEND_WAL_WRITE);
     }
 
-    private void makeWriteOffsetMatchWindow(long newWindowEndOffset) throws IOException, OverCapacityException {
+    private void makeWriteOffsetMatchWindow(long newWindowEndOffset) throws IOException {
         // align to block size
         newWindowEndOffset = WALUtil.alignLargeByBlockSize(newWindowEndOffset);
         long windowStartOffset = windowCoreData.getStartOffset();
         long windowMaxLength = windowCoreData.getMaxLength();
         if (newWindowEndOffset > windowStartOffset + windowMaxLength) {
-            long newWindowMaxLength = newWindowEndOffset - windowStartOffset + scaleUnit;
-            if (newWindowMaxLength > upperLimit) {
-                // exceed upper limit
-                if (newWindowEndOffset - windowStartOffset >= upperLimit) {
-                    // however, the new window length is still larger than upper limit, so we just set it to upper limit
-                    newWindowMaxLength = upperLimit;
-                } else {
-                    // the new window length is bigger than upper limit, reject this write request
-                    LOGGER.error("new windows size {} exceeds upper limit {}, reject this write request, window start offset: {}, new window end offset: {}",
-                        newWindowMaxLength, upperLimit, windowStartOffset, newWindowEndOffset);
-                    throw new OverCapacityException(String.format("new windows size exceeds upper limit %d", upperLimit));
-                }
-            }
+            // endOffset - startOffset <= block.maxSize <= upperLimit in {@link #sealAndNewBlockLocked}
+            assert newWindowEndOffset - windowStartOffset <= upperLimit;
+            long newWindowMaxLength = Math.min(newWindowEndOffset - windowStartOffset + scaleUnit, upperLimit);
             windowCoreData.scaleOutWindow(walHeaderFlusher, newWindowMaxLength);
         }
     }
diff --git a/s3stream/src/main/java/com/automq/stream/s3/wal/benchmark/WriteBench.java b/s3stream/src/main/java/com/automq/stream/s3/wal/benchmark/WriteBench.java
index 28e26393b..f50042617 100644
--- a/s3stream/src/main/java/com/automq/stream/s3/wal/benchmark/WriteBench.java
+++ b/s3stream/src/main/java/com/automq/stream/s3/wal/benchmark/WriteBench.java
@@ -107,7 +107,7 @@ private static void resetWALHeader(String path) throws IOException {
         }
     }
 
-    private static void logIt(Config config, Stat stat) {
+    private static Runnable logIt(Config config, Stat stat) {
         ScheduledExecutorService statExecutor = Threads.newSingleThreadScheduledExecutor(
             ThreadUtils.createThreadFactory("stat-thread-%d", true), null);
         statExecutor.scheduleAtFixedRate(() -> {
@@ -120,6 +120,7 @@ private static void logIt(Config config, Stat stat) {
                     (double) result.maxCostNanos() / TimeUnit.MILLISECONDS.toNanos(1));
             }
         }, LOG_INTERVAL_SECONDS, LOG_INTERVAL_SECONDS, TimeUnit.SECONDS);
+        return statExecutor::shutdownNow;
     }
 
     private void run(Config config) {
@@ -129,7 +130,7 @@ private void run(Config config) {
             config.threads, ThreadUtils.createThreadFactory("append-thread-%d", false), null);
         AppendTaskConfig appendTaskConfig = new AppendTaskConfig(config);
         Stat stat = new Stat();
-        runTrimTask();
+        Runnable stopTrim = runTrimTask();
         for (int i = 0; i < config.threads; i++) {
             int index = i;
             executor.submit(() -> {
@@ -141,7 +142,7 @@ private void run(Config config) {
                 }
             });
         }
-        logIt(config, stat);
+        Runnable stopLog = logIt(config, stat);
 
         executor.shutdown();
         try {
@@ -151,11 +152,13 @@ private void run(Config config) {
         } catch (InterruptedException e) {
             executor.shutdownNow();
         }
+        stopLog.run();
+        stopTrim.run();
 
         System.out.println("Benchmark finished");
     }
 
-    private void runTrimTask() {
+    private Runnable runTrimTask() {
         ScheduledExecutorService trimExecutor = Threads.newSingleThreadScheduledExecutor(
             ThreadUtils.createThreadFactory("trim-thread-%d", true), null);
         trimExecutor.scheduleAtFixedRate(() -> {
@@ -166,6 +169,7 @@ private void runTrimTask() {
                 e.printStackTrace();
             }
         }, TRIM_INTERVAL_MILLIS, TRIM_INTERVAL_MILLIS, TimeUnit.MILLISECONDS);
+        return trimExecutor::shutdownNow;
     }
 
     private void runAppendTask(int index, AppendTaskConfig config, Stat stat) throws Exception {