On Sunday, December 3, 2017, Tom Lane wrote:
> barbiomalefico@gmail.com writes:
> > I copied the text in the followed by example: SELECT
> to_tsvector('fatal
> > error') @@ to_tsquery('fatal <-> error');
> > but it will always goes in error: ERROR: syntax error in tsquery:
> "fatal
> > <-> error"
> > SQL state: 42601
>
> The described symptoms sound like you're trying to use <-> with a pre-9.6
> server. Since that feature was added in 9.6, it won't work.
>
> We generally don't recommend reading documentation versions that don't
> match your server.
>
>
My interpretation of the doc reading advice is to read the newest version
of the docs to learn about stuff but if you come across any errors, syntax
or otherwise, then read your doc version to see how older releases differ.
Non-bug enhancements to the docs are not usually back-patched and knowing
how current releases work is valuable knowledge to have.
David J.