Dave Page <dpage@postgresql.org> writes:
> Tom Lane wrote:
>> Hm, there is a definitional issue here. Should pg_get_indexdef print
>> this stuff at all when colno is nonzero?
>> ...
>> Dave, I think we put in this variant of the function for pgAdmin ---
>> what does pgAdmin need?
> More is better for us - it saves an ugly query that will get uglier if
> we need to figure out ASC/DESC here too :-)
> I agree that we should have all or nothing though, so I'd like to see
> ASC/DESC and opclass please.
I dug through the archives and found that we've had this discussion
before ;-). The basic argument for having the per-column form of
pg_get_indexdef do what it does was that it's unreasonable for
client-side code to try to disassemble an expression tree string,
whereas extracting opclass info is a relatively straightforward
exercise in joining. There are several past threads about this:
http://archives.postgresql.org/pgsql-hackers/2003-07/msg00083.php
http://archives.postgresql.org/pgsql-general/2005-11/msg01106.php
http://archives.postgresql.org/pgsql-hackers/2006-06/msg00576.php
As of 8.3 that expands into also having to know the meaning of the
bits in indoption[], which is kind of annoying, but not even close
to being in the same league as reverse-compiling expressions.
I think the current API expectation for pg_get_indexdef is that
it produces only the index column/expression, and that we are
very likely to break client-side code if we change that.
I don't have any objection to providing an additional new API that
includes the opclass and ASC/DESC decoration in the output ... other
than that I think it's a bit too late for 8.3; adding a function
would mean forcing initdb, and I don't see any reasonable way to
shoehorn two behaviors into the existing function signature.
Just out of curiosity, why is pgAdmin doing it this way at all?
Seems it would be a lot easier to use the all-columns form of
pg_get_indexdef than to cons up the display from fetches of each
column individually.
regards, tom lane
