Does a varchar field's declared size have any impact in PostgreSQL?
问题 Is VARCHAR(100) any better than VARCHAR(500) from a performance point of view? What about disk usage? Talking about PostgreSQL today, not some database some time in history. 回答1: They are identical. From the PostgreSQL documentation: http://www.postgresql.org/docs/8.3/static/datatype-character.html Tip: There are no performance differences between these three types, apart from increased storage size when using the blank-padded type, and a few extra cycles to check the length when storing into