Amazing. Awesome. Well, but what is it? We could store json data in Pg since PostgreSQL 9.2 – so it's been there for over 12 years now. How is the new shiny thing different? What does it allow you to do?
Let's see if I can shed some light on it…
Continue reading SQL/JSON is here! (kinda “Waiting for Pg 17")
This is not the usual Waiting for post, but something should be said.
Back in March/April of 2022 Andrew Dunstan committed a series of patches that added support for lots of really interesting features from SQL/JSON standard.
While I'm not avid user of json in database, I was very, very happy. Wrote couple of blogposts about it.
Then, around six month later they got reverted.
Lately, since last year, actually, these re-appeared again:
Since they re-appeared I was asked (twice) to write about them in the Waiting for series.
So, I just want to say that while I did notice these changes, and am very happy that they are there, I don't plan on writing Waiting for about them.
The reason is simple: I kinda have the feeling that I already wrote about waiting for them.
What I can say though, is that as soon as PostgreSQL version (be it 17, or any other) will get released with these in there, I will reblog about SQL/JSON, with updated examples, so that this huge functionality, and astounding amount of work by developers and testers, will get as much publicity as it can.
For now: I hope it will make it to Pg 17 release, and even before that I would like to thank everyone involved. By my quick count we have at least nine separate authors, and fifteen reviewers, and this is just across these five commits I mentioned.
THANK YOU – can't wait till I will be able to write about it properly 🙂
Back in March and April I wrote couple of blogposts about upcoming new great feature – full SQL/JSON.
Unfortunately, as of today SQL/JSON has been reverted (removed from sources), both from development version 16, but also from “almost ready" version 15.
There is lengthy discussion about it which you can definitely read if you're so inclined (side note, I didn't catch it immediately, so for future me – RMT is Release Management Team.
Obviously the feature will make its comeback. Whether it will be in 16 or later – can't tell now, but it will definitely reappear.
On 8th of April 2022, Andrew Dunstan committed patch:
Documentation for SQL/JSON features This documents the features added in commits f79b803dcc, f4fb45d15c, 33a377608f, 1a36bc9dba, 606948b058, 49082c2cc3, 4e34747c88, and fadb48b00e. I have cleaned up the aggregate section of the submitted docs, but there is still a deal of copy editing required. However, I thought it best to have some documentation sooner rather than later so testers can have a better idea what they are playing with. Nikita Glukhov Reviewers have included (in no particular order) Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zhihong Yu, Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby. Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru Discussion: https://postgr.es/m/7e2cb85d-24cf-4abb-30a5-1a33715959bd@postgrespro.ru
Continue reading Waiting for PostgreSQL 15 – Documentation for SQL/JSON features
On 4th of April 2022, Andrew Dunstan committed patch:
JSON_TABLE This feature allows jsonb data to be treated as a table and thus used in a FROM clause like other tabular data. Data can be selected from the jsonb using jsonpath expressions, and hoisted out of nested structures in the jsonb to form multiple rows, more or less like an outer join. Nikita Glukhov Reviewers have included (in no particular order) Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zhihong Yu (whose name I previously misspelled), Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby. Discussion: https://postgr.es/m/7e2cb85d-24cf-4abb-30a5-1a33715959bd@postgrespro.ru
On 29th of March 2022, Andrew Dunstan committed patch:
SQL/JSON query functions This introduces the SQL/JSON functions for querying JSON data using jsonpath expressions. The functions are: JSON_EXISTS() JSON_QUERY() JSON_VALUE() All of these functions only operate on jsonb. The workaround for now is to cast the argument to jsonb. JSON_EXISTS() tests if the jsonpath expression applied to the jsonb value yields any values. JSON_VALUE() must return a single value, and an error occurs if it tries to return multiple values. JSON_QUERY() must return a json object or array, and there are various WRAPPER options for handling scalar or multi-value results. Both these functions have options for handling EMPTY and ERROR conditions. Nikita Glukhov Reviewers have included (in no particular order) Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zihong Yu, Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby. Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Continue reading Waiting for PostgreSQL 15 – SQL/JSON query functions
On 28th of March 2022, Andrew Dunstan
Title: Waiting for PostgreSQL 15 – IS JSON predicate
On 28th of March 2022, Andrew Dunstan committed patch:
IS JSON predicate This patch intrdocuces the SQL standard IS JSON predicate. It operates on text and bytea values representing JSON as well as on the json and jsonb types. Each test has an IS and IS NOT variant. The tests are: IS JSON [VALUE] IS JSON ARRAY IS JSON OBJECT IS JSON SCALAR IS JSON WITH | WITHOUT UNIQUE KEYS These are mostly self-explanatory, but note that IS JSON WITHOUT UNIQUE KEYS is true whenever IS JSON is true, and IS JSON WITH UNIQUE KEYS is true whenever IS JSON is true except it IS JSON OBJECT is true and there are duplicate keys (which is never the case when applied to jsonb values). Nikita Glukhov Reviewers have included (in no particular order) Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zihong Yu, Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby. Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Continue reading Waiting for PostgreSQL 15 – IS JSON predicate
On 27th of March 2022, Andrew Dunstan committed patch:
SQL/JSON constructors This patch introduces the SQL/JSON standard constructors for JSON: JSON() JSON_ARRAY() JSON_ARRAYAGG() JSON_OBJECT() JSON_OBJECTAGG() For the most part these functions provide facilities that mimic existing json/jsonb functions. However, they also offer some useful additional functionality. In addition to text input, the JSON() function accepts bytea input, which it will decode and constuct a json value from. The other functions provide useful options for handling duplicate keys and null values. This series of patches will be followed by a consolidated documentation patch. Nikita Glukhov Reviewers have included (in no particular order) Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zihong Yu, Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby. Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Continue reading Waiting for PostgreSQL 15 – SQL/JSON constructors
On 16th of March 2019, Alexander Korotkov committed patch:
Partial implementation of SQL/JSON path language SQL 2016 standards among other things contains set of SQL/JSON features for JSON processing inside of relational database. The core of SQL/JSON is JSON path language, allowing access parts of JSON documents and make computations over them. This commit implements partial support JSON path language as separate datatype called "jsonpath". The implementation is partial because it's lacking datetime support and suppression of numeric errors. Missing features will be added later by separate commits. Support of SQL/JSON features requires implementation of separate nodes, and it will be considered in subsequent patches. This commit includes following set of plain functions, allowing to execute jsonpath over jsonb values: * jsonb_path_exists(jsonb, jsonpath[, jsonb, bool]), * jsonb_path_match(jsonb, jsonpath[, jsonb, bool]), * jsonb_path_query(jsonb, jsonpath[, jsonb, bool]), * jsonb_path_query_array(jsonb, jsonpath[, jsonb, bool]). * jsonb_path_query_first(jsonb, jsonpath[, jsonb, bool]). This commit also implements "jsonb @? jsonpath" and "jsonb @@ jsonpath", which are wrappers over jsonpath_exists(jsonb, jsonpath) and jsonpath_predicate(jsonb, jsonpath) correspondingly. These operators will have an index support (implemented in subsequent patches). Catversion bumped, to add new functions and operators. Code was written by Nikita Glukhov and Teodor Sigaev, revised by me. Documentation was written by Oleg Bartunov and Liudmila Mantrova. The work was inspired by Oleg Bartunov. Discussion: https://postgr.es/m/-b497-f39a-923d-%402ndQuadrant.com Author: Nikita Glukhov, Teodor Sigaev, Alexander Korotkov, Oleg Bartunov, Liudmila Mantrova
Continue reading Waiting for PostgreSQL 12 – Partial implementation of SQL/JSON path language