diff --git a/src/frontend/src/optimizer/plan_node/stream_sink.rs b/src/frontend/src/optimizer/plan_node/stream_sink.rs
index 7a9b85a3e1cf6..7bdcb7c45fa8b 100644
--- a/src/frontend/src/optimizer/plan_node/stream_sink.rs
+++ b/src/frontend/src/optimizer/plan_node/stream_sink.rs
@@ -34,6 +34,7 @@ use risingwave_connector::sink::{
     SINK_TYPE_UPSERT, SINK_USER_FORCE_APPEND_ONLY_OPTION,
 };
 use risingwave_pb::stream_plan::stream_node::PbNodeBody;
+use risingwave_pb::stream_plan::SinkLogStoreType;
 
 use super::derive::{derive_columns, derive_pk};
 use super::generic::GenericPlanRef;
@@ -54,11 +55,16 @@ pub struct StreamSink {
     pub base: PlanBase<Stream>,
     input: PlanRef,
     sink_desc: SinkDesc,
+    default_log_store_type: SinkLogStoreType,
 }
 
 impl StreamSink {
     #[must_use]
-    pub fn new(input: PlanRef, sink_desc: SinkDesc) -> Self {
+    pub fn new(
+        input: PlanRef,
+        sink_desc: SinkDesc,
+        default_log_store_type: SinkLogStoreType,
+    ) -> Self {
         let base = input
             .plan_base()
             .into_stream()
@@ -68,6 +74,7 @@ impl StreamSink {
             base,
             input,
             sink_desc,
+            default_log_store_type,
         }
     }
 
@@ -109,7 +116,7 @@ impl StreamSink {
             |sink: &str| Err(SinkError::Config(anyhow!("unsupported sink type {}", sink)));
 
         // check and ensure that the sink connector is specified and supported
-        match sink.properties.get(CONNECTOR_TYPE_KEY) {
+        let default_sink_decouple_fn = match sink.properties.get(CONNECTOR_TYPE_KEY) {
             Some(connector) => {
                 match_sink_name_str!(
                     connector.to_lowercase().as_str(),
@@ -119,20 +126,27 @@ impl StreamSink {
                         if connector == TABLE_SINK && sink.target_table.is_none() {
                             unsupported_sink(TABLE_SINK)
                         } else {
-                            Ok(())
+                            Ok(SinkType::default_sink_decouple as for<'a> fn(&'a SinkDesc) -> bool)
                         }
                     },
                     |other: &str| unsupported_sink(other)
-                )?;
+                )?
             }
             None => {
                 return Err(
                     SinkError::Config(anyhow!("connector not specified when create sink")).into(),
                 );
             }
-        }
+        };
+
+        let default_sink_decouple = default_sink_decouple_fn(&sink);
+        let default_log_store_type = if default_sink_decouple {
+            SinkLogStoreType::KvLogStore
+        } else {
+            SinkLogStoreType::InMemoryLogStore
+        };
 
-        Ok(Self::new(input, sink))
+        Ok(Self::new(input, sink, default_log_store_type))
     }
 
     #[allow(clippy::too_many_arguments)]
@@ -407,7 +421,7 @@ impl PlanTreeNodeUnary for StreamSink {
     }
 
     fn clone_with_input(&self, input: PlanRef) -> Self {
-        Self::new(input, self.sink_desc.clone())
+        Self::new(input, self.sink_desc.clone(), self.default_log_store_type)
         // TODO(nanderstabel): Add assertions (assert_eq!)
     }
 }
@@ -461,24 +475,7 @@ impl StreamNode for StreamSink {
             sink_desc: Some(self.sink_desc.to_proto()),
             table: Some(table.to_internal_table_prost()),
             log_store_type: match self.base.ctx().session_ctx().config().sink_decouple() {
-                SinkDecouple::Default => {
-                    let enable_sink_decouple =
-                        match_sink_name_str!(
-                        self.sink_desc.properties.get(CONNECTOR_TYPE_KEY).expect(
-                            "have checked connector is contained when create the `StreamSink`"
-                        ).to_lowercase().as_str(),
-                        SinkTypeName,
-                        SinkTypeName::default_sink_decouple(&self.sink_desc),
-                        |_unsupported| unreachable!(
-                            "have checked connector is supported when create the `StreamSink`"
-                        )
-                    );
-                    if enable_sink_decouple {
-                        SinkLogStoreType::KvLogStore as i32
-                    } else {
-                        SinkLogStoreType::InMemoryLogStore as i32
-                    }
-                }
+                SinkDecouple::Default => self.default_log_store_type as i32,
                 SinkDecouple::Enable => SinkLogStoreType::KvLogStore as i32,
                 SinkDecouple::Disable => SinkLogStoreType::InMemoryLogStore as i32,
             },