class Storage():
def __init__(self, db_path):
self._current_memtable = Memtable()
self._sstable_group = SSTableGroup.from_directory(db_path)
pass
def put(self, key, value):
self._current_memtable.put(key, value)
# TODO: Check memtable size
# If it's smaller than THRESHOLD:
# Add key to memtable
# Otherwise:
# Write memtable to the new SSTable on disk(table + table index)
# Load that SSTable's index into memory
# Create new memtable
# Add key to the new memtable
def delete(self, key):
# TODO: Same as put
self._current_memtable.delete(key)
def get(self, key):
result = self._current_memtable.get(key)
if result is not None:
return result.get_value()
result = self._sstable_group.get(key)
if result is not None:
return result.get_value()
return None
def test_deletion():
memtable = Memtable()
memtable.put("key1", "value1")
memtable.put("key1", "value1-changed")
memtable.delete("key1")
assert memtable.get('key1').is_tombstone() == True
def test_retrieval():
memtable = Memtable()
memtable.put("key1", "value1")
memtable.put("key2", "value2")
memtable.put("key2", "value2-changed")
assert memtable.get('key1') == Item('key1', "value1", False)
assert memtable.get('key2') == Item('key2', "value2-changed", False)