diff --git a/fe/fe-core/src/main/java/org/apache/doris/planner/OlapScanNode.java b/fe/fe-core/src/main/java/org/apache/doris/planner/OlapScanNode.java
index 49d961be5c8228..68be7541043fe8 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/planner/OlapScanNode.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/planner/OlapScanNode.java
@@ -1344,6 +1344,8 @@ public boolean getShouldColoScan() {
     // If scan is key search, should not enable the shared scan opt to prevent the performance problem
     // 1. where contain the eq or in expr of key column slot
     // 2. key column slot is distribution column and first column
+    // FIXME: this is not a good check, we can not guarantee that the predicate we check can truly
+    // help to prune the data, so we should check the predicate's effect on the data.
     protected boolean isKeySearch() {
         List<SlotRef> whereSlot = Lists.newArrayList();
         for (Expr conjunct : conjuncts) {
diff --git a/fe/fe-core/src/main/java/org/apache/doris/planner/ScanNode.java b/fe/fe-core/src/main/java/org/apache/doris/planner/ScanNode.java
index 648eac047d450c..99184df1453759 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/planner/ScanNode.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/planner/ScanNode.java
@@ -708,7 +708,7 @@ public boolean shouldDisableSharedScan() {
         return isKeySearch() || !enableShardScan;
     }
 
-    public boolean haveLimitAndConjunts() {
-        return hasLimit() && !conjuncts.isEmpty();
+    public boolean shouldUseOneInstance() {
+        return hasLimit() && conjuncts.isEmpty();
     }
 }
diff --git a/fe/fe-core/src/main/java/org/apache/doris/qe/Coordinator.java b/fe/fe-core/src/main/java/org/apache/doris/qe/Coordinator.java
index d0f03aa00e1b77..96ed3649007a4a 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/qe/Coordinator.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/qe/Coordinator.java
@@ -1752,9 +1752,9 @@ private void computeFragmentHosts() throws Exception {
                                 //the scan instance num should not larger than the tablets num
                                 expectedInstanceNum = Math.min(perNodeScanRanges.size(), parallelExecInstanceNum);
                             }
-                            // if have limit and conjunts, only need 1 instance to save cpu and
+                            // if have limit and no conjuncts, only need 1 instance to save cpu and
                             // mem resource
-                            if (node.isPresent() && node.get().haveLimitAndConjunts()) {
+                            if (node.isPresent() && node.get().shouldUseOneInstance()) {
                                 expectedInstanceNum = 1;
                             }
 
@@ -1765,9 +1765,9 @@ private void computeFragmentHosts() throws Exception {
                             int expectedInstanceNum = Math.min(parallelExecInstanceNum,
                                     leftMostNode.getNumInstances());
                             expectedInstanceNum = Math.max(expectedInstanceNum, 1);
-                            // if have limit and conjunts, only need 1 instance to save cpu and
+                            // if have limit and conjuncts, only need 1 instance to save cpu and
                             // mem resource
-                            if (node.isPresent() && node.get().haveLimitAndConjunts()) {
+                            if (node.isPresent() && node.get().shouldUseOneInstance()) {
                                 expectedInstanceNum = 1;
                             }