Leonardo Francalanci <m_lists@yahoo.it> wrote:
>>> another question regarding indexes. Sadly I can't find enough
>>> info in the documentation. Which of the functions are needed in
>>> order for a index to work?
>>
>> All of them.
>
>
> Maybe I completely misunderstood the question, but some functions
> are "optionals", such as amgetbitmap, right?
>
> http://www.postgresql.org/docs/9.0/static/index-functions.html
Browsing that page, I think these are the two relevant bits
regarding exceptions to the rule:
| The amgettuple function need only be provided if the access method
| supports "plain" index scans. If it doesn't, the amgettuple field
| in its pg_am row must be set to zero.
| The amgetbitmap function need only be provided if the access
| method supports "bitmap" index scans. If it doesn't, the
| amgetbitmap field in its pg_am row must be set to zero.
I have no idea which of these would be useful for the AM being
discussed.
-Kevin