feat: compact when the buffers are empty or if more than u16::MAX (#5166)

Signed-off-by: Daniel King <[email protected]>

Author: danking

vortex-array/src/arrays/varbinview/compact.rs

@@ -33,17 +33,24 @@ impl VarBinViewArray {
     }
 
     fn should_compact(&self) -> bool {
+        let nbuffers = self.nbuffers();
+
         // If the array is entirely inlined strings, do not attempt to compact.
-        if self.nbuffers() == 0 {
+        if nbuffers == 0 {
             return false;
         }
 
+        // These will fail to write, so in most cases we want to compact this.
+        if nbuffers > u16::MAX as usize {
+            return true;
+        }
+
         let bytes_referenced: u64 = self.count_referenced_bytes();
         let buffer_total_bytes: u64 = self.buffers.iter().map(|buf| buf.len() as u64).sum();
 
         // If there is any wasted space, we want to repack.
         // This is very aggressive.
-        bytes_referenced < buffer_total_bytes
+        bytes_referenced < buffer_total_bytes || buffer_total_bytes == 0
     }
 
     // count the number of bytes addressed by the views, not including null