diff --git a/s3stream/src/main/java/com/automq/stream/s3/S3Storage.java b/s3stream/src/main/java/com/automq/stream/s3/S3Storage.java
index 11ab16d80..966623d4e 100644
--- a/s3stream/src/main/java/com/automq/stream/s3/S3Storage.java
+++ b/s3stream/src/main/java/com/automq/stream/s3/S3Storage.java
@@ -545,7 +545,9 @@ private void handleAppendCallback0(WalWriteRequest request) {
             waitingAckRequests = callbackSequencer.after(request);
             waitingAckRequests.forEach(r -> r.record.retain());
             for (WalWriteRequest waitingAckRequest : waitingAckRequests) {
-                if (deltaWALCache.put(waitingAckRequest.record)) {
+                boolean full = deltaWALCache.put(waitingAckRequest.record);
+                waitingAckRequest.confirmed = true;
+                if (full) {
                     // cache block is full, trigger WAL upload.
                     uploadDeltaWAL();
                 }
@@ -766,7 +768,7 @@ synchronized private long calculate() {
                 }
                 WalWriteRequest request = wrapper.request;
                 assert request.offset != NOOP_OFFSET;
-                if (!request.persisted) {
+                if (!request.confirmed) {
                     minUnconfirmedOffset = Math.min(minUnconfirmedOffset, request.offset);
                 }
             }
@@ -783,7 +785,7 @@ synchronized private long calculate() {
                     break;
                 }
                 WalWriteRequest request = wrapper.request;
-                if (request.persisted && request.offset < minUnconfirmedOffset) {
+                if (request.confirmed && request.offset < minUnconfirmedOffset) {
                     confirmedOffset = Math.max(confirmedOffset, request.offset);
                     iterator.remove();
                 }
diff --git a/s3stream/src/main/java/com/automq/stream/s3/WalWriteRequest.java b/s3stream/src/main/java/com/automq/stream/s3/WalWriteRequest.java
index 01919c66f..c843e095f 100644
--- a/s3stream/src/main/java/com/automq/stream/s3/WalWriteRequest.java
+++ b/s3stream/src/main/java/com/automq/stream/s3/WalWriteRequest.java
@@ -11,8 +11,10 @@
 
 package com.automq.stream.s3;
 
+import com.automq.stream.s3.cache.LogCache;
 import com.automq.stream.s3.context.AppendContext;
 import com.automq.stream.s3.model.StreamRecordBatch;
+import com.automq.stream.s3.wal.WriteAheadLog;
 import java.util.concurrent.CompletableFuture;
 
 public class WalWriteRequest implements Comparable<WalWriteRequest> {
@@ -20,8 +22,22 @@ public class WalWriteRequest implements Comparable<WalWriteRequest> {
     final AppendContext context;
     final CompletableFuture<Void> cf;
     long offset;
+    /**
+     * Whether the record has been persisted to the {@link WriteAheadLog}
+     * When a continuous series of records IN A STREAM have been persisted to the WAL, they can be uploaded to S3.
+     *
+     * @see S3Storage.WALCallbackSequencer
+     */
     boolean persisted;
 
+    /**
+     * Whether the record has been put to the {@link LogCache}
+     * When a continuous series of records have been persisted to the WAL and uploaded to S3, they can be trimmed.
+     *
+     * @see S3Storage.WALConfirmOffsetCalculator
+     */
+    boolean confirmed;
+
     public WalWriteRequest(StreamRecordBatch record, long offset, CompletableFuture<Void> cf) {
         this(record, offset, cf, AppendContext.DEFAULT);
     }
@@ -44,6 +60,7 @@ public String toString() {
             "record=" + record +
             ", offset=" + offset +
             ", persisted=" + persisted +
+            ", confirmed=" + confirmed +
             '}';
     }
 }
diff --git a/s3stream/src/test/java/com/automq/stream/s3/S3StorageTest.java b/s3stream/src/test/java/com/automq/stream/s3/S3StorageTest.java
index 3413b65c9..f7b8f4a8f 100644
--- a/s3stream/src/test/java/com/automq/stream/s3/S3StorageTest.java
+++ b/s3stream/src/test/java/com/automq/stream/s3/S3StorageTest.java
@@ -135,19 +135,19 @@ public void testWALConfirmOffsetCalculator() {
         calc.update();
         assertEquals(-1L, calc.get());
 
-        r0.persisted = true;
+        r0.confirmed = true;
         calc.update();
         assertEquals(0L, calc.get());
 
-        r3.persisted = true;
+        r3.confirmed = true;
         calc.update();
         assertEquals(0L, calc.get());
 
-        r1.persisted = true;
+        r1.confirmed = true;
         calc.update();
         assertEquals(1L, calc.get());
 
-        r2.persisted = true;
+        r2.confirmed = true;
         calc.update();
         assertEquals(3L, calc.get());
     }