Amazon Redshift distributes the data across all slices and divides them into columns. The columns of a row are assigned to blocks so they can easily be found together again. Each block contains metadata that stores the value range of the block. This helps not to read blocks if they do not include the values you are looking for. Teradata offers columnar table storage in different ways, but it retrieves the data from the column containers, decompresses it, and reconstructs rows. In a subsequent step, the row-based traditional database engine works but operates on the already decompressed data. This shows that Teradata was not initially designed as a columnar database.