On 02/25/2014 09:45 AM, Bruce Momjian wrote: >> It hurts our adoption substantially to confuse developers. We need to >> recommend one type over the other, hence "Use jsonb unless you need X". >> Merlin is pushing the type of multivariable comparison where *I* >> wouldn't be able to make sense of which one I should pick, let alone >> some web developer who's just trying to get a site built. That sort of >> thing *really* doesn't help our users. > > I agree it would be nice to have something simple, like "Use JSON if you > wish to just store/retrieve entire JSON structures, and JSONB if you > wish to do any kind of lookup or manipulation of JSON values on the > server".
(to clarify below: "json" refers to the current varlena datatype; JSON refers to JSON serialized data). I don't think that's decisive enough, which is why I wrote the doc the way I did. The problem is that most users would prefer that we tell them which one to use, which is why I want to structure the doc as "Use jsonb unless you need one of these things", or more specifically: In general, most applications will find it advantageous to store JSON data as <type>jsonb</type>, as jsonb is more efficient when using JSON manipulation functions, and will support future advanced json index, operator and search features. The <type>json</type> will primarily be useful for applications which need to preserve exact formatting of the input JSON, or users with existing <type>json</type> columns which they do not want to convert to <type>jsonb</type>. Part of my reason for wanting to recommend jsonb over json is in the context of the third storage option for JSON, namely TEXT. The only things which distinguish json from TEXT for JSON storage are validation and a set of json manipulation functions. jsonb works with the manipulation functions better/faster, causing the old json type to start looking like more of a DOMAIN over TEXT than a real type comparatively. In other words, if you ask the question "Why would I want to use json instead of either jsonb or TEXT", the answer becomes quite narrow. Possibly I should expand the little chart and add a column for TEXT? It's a viable option for storing JSON data, especially if you store a lot of broken JSON or fragments. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers