Re: SQL/JSON in PostgreSQL

On 03.11.2017 15:07, Michael Paquier wrote:

> On Fri, Nov 3, 2017 at 11:29 AM, Nikita Glukhov <n(dot)gluhov(at)postgrespro(dot)ru> wrote:
>> By standard only string literals can be used in JSON path specifications.
>> But of course it is possible to allow to use variable jsonpath expressions
>> in
>> SQL/JSON functions.
>>
>> Attached patch implements this feature for JSON query functions, JSON_TABLE
>> is
>> not supported now because it needs some refactoring.
>>
>> I have pushed this commit to the separate branch because it is not finished
>> yet:
>> https://github.com/postgrespro/sqljson/tree/sqljson_variable_json_path
> The patch sent previously does not directly apply on HEAD, and as far
> as I can see the last patch set published on
> https://www.postgresql.org/message-id/2361ae4a-66b1-c6c5-ea6a-84851a1c08b5@postgrespro.ru
> has rotten. Could you send a new patch set?
Attached patch set rebased onto current master.
Branches in our github repository also updated.

> About the patch set, I had a look at the first patch which is not that
> heavy, however it provides zero documentation, close to zero comments,
> but adds more than 500 lines of code. I find that a bit hard to give
> an opinion on, having commit messages associated to each patch would
> be also nice. This way, reviewers can figure what's going out in this
> mess and provide feedback.
Sorry that comments and commit messages are still absent. I am going to
do it
in the next version of these patches where SQL/JSON constructors displaying
will be fixed.

> Making things incremental is welcome as
> well, for example in the first patch I have a hard way finding out why
> timestamps are touched to begin with.
Timestamp's code was touched to add support of two features needed for
SQL/JSON
 .datetime() item method by standard:
 - TZH and TZM template patterns
 - datetime components recognition

I absolutely agree that this should be in a separate patch.

> The patch is already marked as "waiting on author" for more than one month.
--
Nikita Glukhov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company