2011/8/3 Raj Mathur (राज माथुर) <r...@linux-delhi.org>: > Hi, > > Can you point me to any pages that explain the difference between using, > say CHAR(8) vs VARCHAR(8) as the primary key for a table? Is there any > impact on the database in terms of: > > - Speed of indexed retrieval > - Speed of join from a referencing table > - Storage (I presume VARHAR(8) would have a slight edge, in general) > - Any other issue
The docs have good info about the differences between these types: http://www.postgresql.org/docs/current/static/datatype-character.html I suspect the tiny size differences between char(8) and varchar(8) are going to be negligible. In fact, this post talks precisely about this concern, and more: http://www.depesz.com/index.php/2010/03/02/charx-vs-varcharx-vs-varchar-vs-text/ Personally I'd be most worried about the different semantics of the types (i.e. treatment of trailing spaces), and perhaps the ease of expanding the length constraint in the future. Josh -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
