diff --git a/flink-doris-connector/src/main/java/org/apache/doris/flink/backend/BackendClient.java b/flink-doris-connector/src/main/java/org/apache/doris/flink/backend/BackendClient.java
index 319fda82a..be976eff1 100644
--- a/flink-doris-connector/src/main/java/org/apache/doris/flink/backend/BackendClient.java
+++ b/flink-doris-connector/src/main/java/org/apache/doris/flink/backend/BackendClient.java
@@ -134,19 +134,16 @@ private void close() {
      * @throws ConnectedFailedException throw if cannot connect to Doris BE
      */
     public TScanOpenResult openScanner(TScanOpenParams openParams) {
-        logger.info(
-                "OpenScanner to '{}', table is '{}', tablets is '{}'",
-                routing,
-                openParams.table,
-                openParams.tablet_ids);
+        logger.debug("OpenScanner to '{}', parameter is '{}'.", routing, openParams);
         if (!isConnected) {
             open();
         }
         TException ex = null;
+        TScanOpenResult result = null;
         for (int attempt = 0; attempt < retries; ++attempt) {
             logger.debug("Attempt {} to openScanner {}.", attempt, routing);
             try {
-                TScanOpenResult result = client.openScanner(openParams);
+                result = client.openScanner(openParams);
                 if (result == null) {
                     logger.warn("Open scanner result from {} is null.", routing);
                     continue;
@@ -159,16 +156,29 @@ public TScanOpenResult openScanner(TScanOpenParams openParams) {
                             result.getStatus().getErrorMsgs());
                     continue;
                 }
+                logger.info(
+                        "OpenScanner success for Doris BE '{}' with contextId '{}' for tablets '{}'.",
+                        routing,
+                        result.getContextId(),
+                        openParams.tablet_ids);
                 return result;
             } catch (TException e) {
                 logger.warn("Open scanner from {} failed.", routing, e);
                 ex = e;
             }
         }
-        logger.error(
-                "Connect to doris {} failed, to open scanner for tablet {}",
-                routing,
-                openParams.tablet_ids);
+        if (result != null && (TStatusCode.OK != (result.getStatus().getStatusCode()))) {
+            logger.error(
+                    ErrorMessages.DORIS_INTERNAL_FAIL_MESSAGE,
+                    routing,
+                    result.getStatus().getStatusCode(),
+                    result.getStatus().getErrorMsgs());
+            throw new DorisInternalException(
+                    routing.toString(),
+                    result.getStatus().getStatusCode(),
+                    result.getStatus().getErrorMsgs());
+        }
+        logger.error(ErrorMessages.CONNECT_FAILED_MESSAGE, routing);
         throw new ConnectedFailedException(routing.toString(), ex);
     }
 
@@ -251,7 +261,10 @@ public void closeScanner(TScanCloseParams closeParams) {
                 logger.warn("Close scanner from {} failed.", routing, e);
             }
         }
-        logger.info("CloseScanner to Doris BE '{}' success.", routing);
+        logger.info(
+                "CloseScanner to Doris BE '{}' success for contextId {} ",
+                routing,
+                closeParams.getContextId());
         close();
     }
 }
diff --git a/flink-doris-connector/src/main/java/org/apache/doris/flink/source/assigners/SimpleSplitAssigner.java b/flink-doris-connector/src/main/java/org/apache/doris/flink/source/assigners/SimpleSplitAssigner.java
index 7948244ca..57a56f53f 100644
--- a/flink-doris-connector/src/main/java/org/apache/doris/flink/source/assigners/SimpleSplitAssigner.java
+++ b/flink-doris-connector/src/main/java/org/apache/doris/flink/source/assigners/SimpleSplitAssigner.java
@@ -45,9 +45,9 @@ public Optional<DorisSourceSplit> getNext(@Nullable String hostname) {
     }
 
     @Override
-    public void addSplits(Collection<DorisSourceSplit> splits) {
-        LOG.info("Adding splits: {}", splits);
-        splits.addAll(splits);
+    public void addSplits(Collection<DorisSourceSplit> newSplits) {
+        LOG.info("Adding splits: {}", newSplits);
+        splits.addAll(newSplits);
     }
 
     @Override
diff --git a/flink-doris-connector/src/main/java/org/apache/doris/flink/table/DorisTableInputSplit.java b/flink-doris-connector/src/main/java/org/apache/doris/flink/table/DorisTableInputSplit.java
index 9620c5754..9abe15f2c 100644
--- a/flink-doris-connector/src/main/java/org/apache/doris/flink/table/DorisTableInputSplit.java
+++ b/flink-doris-connector/src/main/java/org/apache/doris/flink/table/DorisTableInputSplit.java
@@ -39,4 +39,15 @@ public DorisTableInputSplit(int splitNumber, PartitionDefinition partition) {
     public int getSplitNumber() {
         return splitNumber;
     }
+
+    @Override
+    public String toString() {
+        return String.format(
+                "DorisTableInputSplit: %s.%s,id=%s,be=%s,tablets=%s",
+                partition.getDatabase(),
+                partition.getTable(),
+                splitNumber,
+                partition.getBeAddress(),
+                partition.getTabletIds());
+    }
 }