Re: Add jsonb_compact(...) for whitespace-free jsonb to text - Mailing list pgsql-hackers

From Stephen Frost
Subject Re: Add jsonb_compact(...) for whitespace-free jsonb to text
Date
Msg-id 20160425012733.GT10850@tamriel.snowman.net
Whole thread Raw
In response to Re: Add jsonb_compact(...) for whitespace-free jsonb to text  (Andrew Dunstan <andrew@dunslane.net>)
Responses Re: Add jsonb_compact(...) for whitespace-free jsonb to text  (Sehrope Sarkuni <sehrope@jackdb.com>)
List pgsql-hackers
* Andrew Dunstan (andrew@dunslane.net) wrote:
> On 04/24/2016 06:02 PM, Sehrope Sarkuni wrote:
> >AFAIK, there's also no guarantee on the specific order of the
> >resulting properties in the text representation either. I would
> >suppose it's fixed for a given jsonb value within a database major
> >version but across major versions it could change (if the
> >underlying representation changes).
>
> The order is fixed and very unlikely to change, as it was chosen
> quite deliberately to help ensure efficient processing. Any change
> in on-disk representation of data types is something we work very
> hard to avoid, as it makes it impossible to run pg_upgrade.

We do, from time-to-time, change on-disk formats in a
backwards-compatible way though.  In any case, it's my understanding
that we don't *guarantee* any ordering currently and therefore we should
discourage users from depending on it.  If we *are* going to guarantee
ordering, then we should document what that ordering is.

Thanks!

Stephen

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