src/columnar_storage/src/manifest/mod.rs (2 lines):
	- line 151: // TODO: sort files in payload, so we can delete files more
	- line 159: // TODO: avoid clone


src/columnar_storage/src/read.rs (2 lines):
	- line 274: lhs_col, rhs_col, lhs_idx, rhs_idx, // TODO: Add more types here
	- line 477: // TODO: fetch using multiple threads since read from parquet will incur CPU


src/columnar_storage/src/compaction/executor.rs (2 lines):
	- line 153: // TODO: Merge input sst files into one new sst file
	- line 185: // TODO: support multi-part write


src/columnar_storage/src/manifest/encoding.rs (1 line):
	- line 304: // TODO: Ensure no files duplicated