fix conversation

Author: TCeason

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

@@ -71,17 +71,13 @@ impl FixedSizeBinaryColumnBuilder {
     }
 
     pub fn is_empty(&self) -> bool {
-        self.len() <= 1
+        self.len() < 1
     }
 
     pub fn memory_size(&self) -> usize {
         self.data.len()
     }
 
-    pub fn put_u8(&mut self, item: u8) {
-        self.data.push(item);
-    }
-
     pub fn push_default(&mut self) {
         self.data.extend_from_slice(&vec![0; self.value_length]);
     }

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