Re: Can this function be declared IMMUTABLE?

"Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> beickhof(at)Lexmark(dot)com writes:
>> Well, I am considering a function that does select from a table, but the
>> table contents change extremely infrequently (the table is practically a
>> list of constants). Would it be safe to declare the function IMMUTABLE
>> provided that the table itself is endowed with a trigger that will drop
>> and recreate the function any time the table contents are modified?
>
> What you'd want to do is restart all existing sessions so that any plans
> made using precomputed function values are discarded. The trigger you
> suggest is fairly pointless because it will not cause regeneration of
> plans.

The trigger would alert him if there were any indexes built using the
function...

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com