json datatype and table bloat?
От | Adam Jelinek |
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Тема | json datatype and table bloat? |
Дата | |
Msg-id | CAMwTJE6qLvY9Te1nifXXjNVw34JxG1SRFK2e2+jrCB8vTOH3Vw@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: json datatype and table bloat? (Merlin Moncure <mmoncure@gmail.com>) |
Ответы |
Re: json datatype and table bloat?
|
Список | pgsql-general |
Along the lines of the equality operator; I have ran into issues trying to pivot a table/result set with a json type due what seemed to be no equality operator.
On Nov 4, 2013 10:14 AM, "Merlin Moncure" <mmoncure@gmail.com> wrote:
On Fri, Nov 1, 2013 at 1:50 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Gregory Haase <haaseg@onefreevoice.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
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