Re: json datatype and table bloat?

On Fri, Nov 1, 2013 at 1:50 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Gregory Haase <haaseg(at)onefreevoice(dot)com> writes:
>> The json_data column is not accounted for in pg_stats:
>
> Ah! I hadn't twigged to the fact that your bloat measurement approach
> assumed you had pg_stats entries for all the columns.
>
>> So I'm not sure if I'd actually qualify this as a "bug", but it appears
>> that there is no way to currently get stats on a json data type.
>
> ANALYZE currently punts on columns that don't have an equality operator,
> which json does not. There isn't that much in the way of stats that we
> could collect, though I suppose we could still compute average datum width
> and null fraction.
>
> I'm not sure whether there are plans to invent an equality operator for
> json.

IMNSO, this may not be a bug, but it's pretty close. All base types
should have equality operator as well as other supporting
infrastructure that the database itself depends on (in/out and
send/receive for example). This is a pretty good example of why.

merlin