Re: string_to_array has to be stable? - Mailing list pgsql-hackers

From Jeff Davis
Subject Re: string_to_array has to be stable?
Date
Msg-id 1280364669.31397.8.camel@jdavis-ux.asterdata.local
Whole thread Raw
In response to Re: string_to_array has to be stable?  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: string_to_array has to be stable?
List pgsql-hackers
On Wed, 2010-07-28 at 20:25 -0400, Tom Lane wrote:
> string_to_array() seems fine to me: it's a predictable transformation
> from text to text.  However, I think that there really is an issue with
> array_to_string(), because that takes an anyarray and invokes the array
> element's type output function. 

Yes, I misread the problem because he used "current_date" rather than a
date literal.

> I can't remember offhand whether there are any volatile type output
> functions, but if there were we'd really need to mark array_to_string()
> as volatile.  That would be unpleasant for performance though.   I'd
> rather compromise on stable.  Thoughts?

"Stable" seems reasonable to me.

A volatile type output function sounds like an edge case. Perhaps there
are even grounds to force a type output function to be stable, similar
to how we force the function for a functional index to be immutable.

Regards,Jeff Davis



pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: string_to_array has to be stable?
Next
From: Florian Pflug
Date:
Subject: Re: Patch to show individual statement latencies in pgbench output