> PostgreSQL stores each record, regardless of attributes, in an 8K block of data (excluding TOAST fields and indices) on the disk. If you have a table with 5 c

> PostgreSQL stores each record, regardless of attributes, in an 8K block of data (excluding TOAST fields and indices) on the disk. If you have a table with 5 columns of integers they will use 8K of disk space for each row, not 20 bytes. This is wrong. Postgres uses 8KB blocks for heap data by default, but you can (and typically will) have multiple rows in a single page.