On Mon, Sep 16, 2013 at 12:46 PM, Kevin Grittner <kgrittn@ymail.com> wrote:
> Hannu Krosing <hannu@2ndQuadrant.com> wrote:
>
>> What I meant is that rather than leave it really undocumented,
>> document it as "system function for specific usage, has caveats
>> and may change in future versions. use at your own risk and
>> make sure you know what you are doing"
>
> Well, that was my original assumption and intention; but when I
> went to look for where the operators for record *equals* were
> defined, I found that we had apparently chosen to leave them
> undocumented. Oddly, under a section titled "Row-wise Comparison"
> we only document the behavior of comparisons involving what the SQL
> spec calls <row value constructor>. I asked whether that was
> intentional, and heard only the chirping of crickets:
>
> http://www.postgresql.org/message-id/1378848776.70700.YahooMailNeo@web162902.mail.bf1.yahoo.com
>
> If we choose not to document the equals operator for records, it
> hardly makes sense to document the identical operator for records.
>
>> PostgreSQL has good enough introspection features that people
>> tend to find functions and operators using psql-s \d ...
>
> One would think so, yet I don't recall seeing anyone posting
> regarding the existing undocumented record comparison operators.
> Nor do I recall seeing anyone posting about the undocumented
> pattern comparison operators.
This behavior came about via a gripe of mine (but mostly courtesy Tom
Lane_: http://www.postgresql.org/message-id/6EE64EF3AB31D5448D0007DD34EEB34101AEF5@Herge.rcsinc.local
It brought row-wise comparon closer- (if not exactly to-) SQL spec.
The underlying use-case is to do ISAM-like record iteration over the
index. "index" being the operative word.
merlin