diff --git a/hstream-kafka/HStream/Kafka/Server/Handler/Consume.hs b/hstream-kafka/HStream/Kafka/Server/Handler/Consume.hs
index 1e8d64683..3543f0f76 100644
--- a/hstream-kafka/HStream/Kafka/Server/Handler/Consume.hs
+++ b/hstream-kafka/HStream/Kafka/Server/Handler/Consume.hs
@@ -116,6 +116,7 @@ handleFetch sc@ServerContext{..} reqCtx r_ = K.catchFetchResponseEx $ do
           x -> error $ "LogicError: this should not be " <> show x
       pure $ K.FetchableTopicResponse topic (K.NonNullKaArray respPartitionDatas)
     let resp = K.FetchResponse (K.NonNullKaArray respTopics) 0{- TODO: throttleTimeMs -}
+    Log.warning $ "Fetch request return error: " <> Log.build (show resp)
     -- Exit early
     throwIO $ K.FetchResponseEx resp
 
@@ -332,6 +333,7 @@ getPartitionLsn
   -> Int64        -- ^ kafka start offset
   -> IO LsnData
 getPartitionLsn ldclient om logid partition offset = do
+  Log.debug $ "Request partition LSN for logid: " <> Log.build logid <> ", partition: " <> Log.build partition <> ", offset: " <> Log.build offset
   m <- K.getLatestOffsetWithLsn om logid
   case m of
     Just (latestOffset, tailLsn) -> do
@@ -341,14 +343,16 @@ getPartitionLsn ldclient om logid partition offset = do
              Log.debug1 $ "Try findKey " <> Log.buildString' key <> " in logid "
                        <> Log.build logid
              (_, startLsn) <- S.findKey ldclient logid key S.FindKeyStrict
-             Log.debug1 $ "FindKey result " <> Log.build logid <> ": "
-                       <> Log.build startLsn
+             Log.debug1 $ "FindKey for logid " <> Log.build logid <> " get result " <> Log.build startLsn
              pure $ LsnData startLsn tailLsn highwaterOffset
-         | offset == latestOffset ->
+         | offset == latestOffset -> do
+             Log.debug1 $ "offset == latestOffset"
              pure $ LsnData tailLsn tailLsn highwaterOffset
-         | offset == highwaterOffset ->
+         | offset == highwaterOffset -> do
+             Log.debug1 $ "offset == highwaterOffset"
              pure $ LsnData (tailLsn + 1) tailLsn highwaterOffset
-         | offset > highwaterOffset ->
+         | offset > highwaterOffset -> do
+             Log.debug1 $ "offset > highwaterOffset"
              pure $ ErrPartitionData $ errorPartitionResponse partition K.OFFSET_OUT_OF_RANGE
          -- ghc is not smart enough to detact my partten matching is complete
          | otherwise -> error "This should not be reached (getPartitionLsn)"
@@ -389,8 +393,9 @@ readMode1 r storageOpts reader = do
 
       if r.minBytes <= 0 || r.maxWaitMs <= 0 -- respond immediately
          then do
-           Log.debug1 $ "Set reader to nonblocking"
-           S.readerSetTimeout reader 0  -- nonblocking
+           Log.debug1 $ "Set reader wait only when no data and timeout to 10ms"
+           S.readerSetWaitOnlyWhenNoData reader
+           S.readerSetTimeout reader 10
            insertRecords recordTable
              -- For non-empty results
              =<< S.readerReadSome reader storageOpts.fetchMaxLen 10{-retries-}