On Tue, Nov 22, 2016 at 3:56 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Doc: improve documentation about composite-value usage.
Create a section specifically for the syntactic rules around whole-row variable usage, such as expansion of "foo.*". This was previously documented only haphazardly, with some critical info buried in unexpected places like xfunc-sql-composite-functions. Per repeated questions in different mailing lists.
Tom,
I found it notable that you choose to introduce the OFFSET 0 hack instead of writing a LATERAL query in the "optimization failure" example.
SELECT (m).* FROM (SELECT myfunc(x) AS m FROM some_table OFFSET 0) ss;
instead of
SELECT (m).* FROM some_table, LATERAL myfunc(some_table.x) m
Skipping or having a different example in 9.2 seems worth it in order to introduce the now preferred way of writing such queries.
Or maybe in addition, so that some familiarity with the hack is gained should the reader encounter it in the wild.
