self.commit(wtx, value_cache)?;
        value_cache = HashMap::new();
        uncommitted = 0;
        wtx = self.index.begin_write()?;
        let height = wtx
          .open_table(HEIGHT_TO_BLOCK_HASH)?
          .range(0..)?
          .next_back()
          .and_then(|result| result.ok())
          .map(|(height, _hash)| height.value() + 1)
          .unwrap_or(0);
        if height != self.height {
          // another update has run between committing and beginning the new
          // write transaction
          break;
        }
        wtx
          .open_table(WRITE_TRANSACTION_STARTING_BLOCK_COUNT_TO_TIMESTAMP)?
          .insert(
            &self.height,
            &SystemTime::now()
              .duration_since(SystemTime::UNIX_EPOCH)
              .map(|duration| duration.as_millis())
              .unwrap_or(0),
          )?;
      }

      if SHUTTING_DOWN.load(atomic::Ordering::Relaxed) {
        break;
      }
    }

    if uncommitted > 0 {
      self.commit(wtx, value_cache)?;
    }