On Sat, Dec 22, 2012 at 9:31 AM, Adrian Klaver <adrian.klaver@gmail.com> wrote:
> On 12/21/2012 02:22 PM, Chris Angelico wrote:
>> As I understand it, there are three keywords: VOLATILE, STRICT, and
>> IMMUTABLE. Putting one of those keywords into the declaration flags
>> the function accordingly; if none is given, VOLATILE is assumed.
>>
>> Declaring the function as "STRICT IMMUTABLE" or "STRICT VOLATILE"
>> seems at best redundant (the word "STRICT" is mere noise), and at
>> worst confusing (the parser might be interpreting it as "STRICT", not
>> as the other keyword). Or is there something I'm missing here?
>
>
> Not sure I am following.
>
> IMMUTABLE/VOLATILE/STABLE deal with the query optimizer.
>
> CALLED ON NULL INPUT/STRICT deal with NULL input behavior.
>
> http://www.postgresql.org/docs/9.2/interactive/sql-createfunction.html
OOPS! Error's mine, sorry everyone! I thought the keyword was STRICT,
but it's actually STABLE that does that. Apologies to anyone who's
been confused by my miswording in this thread!
STRICT VOLATILE makes perfect sense; STABLE VOLATILE is what doesn't.
ChrisA