code: public void remove(int i, PersistentStore store) {
  
          writeLock.lock();
  
          try {
              CachedObject r = release(i);
  
              if (r != null) {
                  int size = r.getStorageSize();
  
                  freeBlocks.add(i, size);
              }
          } finally {
              writeLock.unlock();
          }
      }
docs: Used when a row is deleted as a result of some DML or DDL statement.
  Removes the row from the cache data structures.
  Adds the file space for the row to the list of free positions.