fix conversation

Author: TCeason

src/common/column/src/fixedsizebinary/builder.rs

@@ -71,7 +71,7 @@ impl FixedSizeBinaryColumnBuilder {
     }
 
     pub fn is_empty(&self) -> bool {
-        self.len() <= 1
+        self.len() < 1
     }
 
     pub fn memory_size(&self) -> usize {

src/common/column/src/fixedsizebinary/mod.rs

@@ -68,7 +68,7 @@ impl FixedSizeBinaryColumn {
     }
 
     pub fn index(&self, index: usize) -> Option<&[u8]> {
-        if index + 1 < self.len() {
+        if index < self.len() {
             Some(&self.data[index..index + self.value_length])
         } else {
             None