Re: SQL/JSON: functions - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: SQL/JSON: functions
Date
Msg-id CAFj8pRCJssezorKkVoc4kXdxUAEE4m-zhg-VHJ2P46xz=y8hhw@mail.gmail.com
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In response to Re: SQL/JSON: functions  (Alexander Korotkov <a.korotkov@postgrespro.ru>)
List pgsql-hackers


2018-03-14 15:11 GMT+01:00 Alexander Korotkov <a.korotkov@postgrespro.ru>:
On Wed, Mar 14, 2018 at 2:10 AM, Andres Freund <andres@anarazel.de> wrote:
On 2018-03-14 07:54:35 +0900, Michael Paquier wrote:
> On Tue, Mar 13, 2018 at 04:08:01PM +0300, Oleg Bartunov wrote:
> > The docs are here
> > https://github.com/obartunov/sqljsondoc/blob/master/README.jsonpath.md
> >
> > It's not easy to write docs for SQL/JSON in xml, so I decided to write in more
> > friendly way. We'll have time to convert it to postgres format.
>
> If you aim at getting a feature committed first without its
> documentation, and getting the docs written after the feature freeze
> using a dedicated open item or such, this is much acceptable in my
> opinion and the CF is running short in time.

Given that this patch still uses PG_TRY/CATCH around as wide paths of
code as a whole ExecEvalExpr() invocation,
 
I agree that we should either use PG_TRY/CATCH over some small and safe
codepaths or surround PG_TRY/CATCH with subtransactions.  PG_TRY/CATCH over
ExecEvalExpr() looks really unacceptable.

basically has gotten no
review, I don't see this going anywhere for v11.

I wouldn't be co categorical at this point.  Patchset is there for about year.
Some parts of code received more of review while some parts receives less.
We can surround all dangerous PG_TRY/CATCH pairs with subtransactions,
tolerate performance penalty and leave further optimizations for future releases.
In worst case, we can remove codepaths which use PG_TRY/CATCH and
leave only ERROR ON ERROR behavior of SQL/JSON.

I am thinking so using subtransactions on few places are acceptable. PLpgSQL uses it years, and it is working good enough.

Regards

Pavel
 

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company 

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