the rule of thumb for me is: - if you have more than one column as PK - and are variable length, or more than 2 columns, fixed length, no bigger than 8 bytes - go for surrogate - always. - if PK is variable length, on average longer than 8 bytes, or can change - go surrogate. - Otherwise leave it as it is. At the end of a day, joining tables, using that have more than 1 variable length key, kills performance. In essence it makes index search a PITA, and should be avoided. This should always be however decision based on query performance, usage, and data types. Never a textbook A or B type of thing. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
