A client provided an MS Access export of their asset database: a table of 330,000 rows by 77 columns. Good ol' Access felt these data needed over 2 Gbytes of storage. I exported the table as a CSV file, about 143 Mbytes and then imported it into PostgreSQL. It needed only 240 Mbytes or so. Queries are much faster than with Access, too. When I made a compressed backup (dump) of the table from PostgreSQL only a modest 7.9 Mbytes was required.