Re: array_to_string(anyarray, text) that was working in 8.1 is not working in 8.3

Huh, I didn't realize that ever worked in the past. I thought the way  
to do what the op describes was to cast it to text[] or whatever  
datatype you from out-of-band knowledge to expect.

-- 
Greg


On 13 Dec 2008, at 19:38, Tom Lane <tgl@sss.pgh.pa.us> wrote:

> Corey Horton <chorton1@austin.rr.com> writes:
>> I'm trying to use array_to_string on the pg_stats column
>> histogram_bounds...
>> test83=# select array_to_string(histogram_bounds::anyarray, '-') from
>> pg_stats where attname = 'id' and tablename = 'widgets';
>> ERROR:  argument declared "anyarray" is not an array but type  
>> anyarray
>> In 8.1, it worked fine...
>
> Hmm.  This seems to have been broken in this patch:
> http://archives.postgresql.org/pgsql-committers/2008-01/msg00173.php
> which was in response to this complaint:
> http://archives.postgresql.org/pgsql-bugs/2008-01/msg00029.php
> and was attempting to prevent that same failure message in a different
> context :-(.  I guess we forgot that pg_statistic makes it possible  
> that
> the *actual* datatype passed to a function could be anyarray.
>
> While we could probably revert just enough of the changes to
> enforce_generic_type_consistency to allow this case again, I wonder
> just how safe that'd really be.  It would amount to expecting that
> functions that take anyarray but don't take or return anyelement to
> not only work on any array type, but to be always prepared for the
> input element type to change on-the-fly (since that's exactly what
> would happen when scanning pg_statistic).  Quite a lot of the built-in
> anyarray functions are prepared to do that, but I'm not sure they all
> are.
>
> Are we prepared to re-open what could be at least a risk of crashing
> bugs, in order to support this type of usage?  I have to admit that
> it's nice to be able to process the pg_statistic columns like this
> --- I've done it myself.  And we'd not heard any reports of problems
> with it before 8.3.
>
>            regards, tom lane
>
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