Month: April 2024

Waiting for …: SQL/JSON is coming back. Hopefully.

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:

  1. Commit by Alvaro Herrera, from March 29th, 2023: SQL/JSON: add standard JSON constructor functions
  2. Commit by Alvaro Herrera, from March 31st, 2023: SQL/JSON: support the IS JSON predicate
  3. Commit by Amit Langote, from July 20th, 2023: Add more SQL/JSON constructor functions
  4. Commit by Amit Langote, from March 21st, 2024: Add SQL/JSON query functions
  5. Commit by Amit Langote, from April 4th, 2024: Add basic JSON_TABLE() functionality

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 🙂

Waiting for PostgreSQL 17 – Invent SERIALIZE option for EXPLAIN.

On 3rd of April 2024, Tom Lane committed patch:

Invent SERIALIZE option for EXPLAIN.
 
EXPLAIN (ANALYZE, SERIALIZE) allows collection of statistics about
the volume of data emitted by a query, as well as the time taken
to convert the data to the on-the-wire format.  Previously there
was no way to investigate this without actually sending the data
to the client, in which case network transmission costs might
swamp what you wanted to see.  In particular this feature allows
investigating the costs of de-TOASTing compressed or out-of-line
data during formatting.
 
Stepan Rutz and Matthias van de Meent,
reviewed by Tomas Vondra and myself
 
Discussion: https://postgr.es/m/ca0adb0e-fa4e-c37e-1cd7-91170b18cae1@gmx.de

Continue reading Waiting for PostgreSQL 17 – Invent SERIALIZE option for EXPLAIN.

Waiting for PostgreSQL 17 – Add new COPY option LOG_VERBOSITY.

On 1st of April 2024, Masahiko Sawada committed patch:

Add new COPY option LOG_VERBOSITY.
 
This commit adds a new COPY option LOG_VERBOSITY, which controls the
amount of messages emitted during processing. Valid values are
'default' and 'verbose'.
 
This is currently used in COPY FROM when ON_ERROR option is set to
ignore. If 'verbose' is specified, a NOTICE message is emitted for
each discarded row, providing additional information such as line
number, column name, and the malformed value. This helps users to
identify problematic rows that failed to load.
 
Author: Bharath Rupireddy
Reviewed-by: Michael Paquier, Atsushi Torikoshi, Masahiko Sawada
Discussion: https://www.postgresql.org/message-id/CALj2ACUk700cYhx1ATRQyRw-fBM%2BaRo6auRAitKGff7XNmYfqQ%40mail.gmail.com

Continue reading Waiting for PostgreSQL 17 – Add new COPY option LOG_VERBOSITY.

Waiting for PostgreSQL 17 – Add support for MERGE … WHEN NOT MATCHED BY SOURCE.

On 30th of March 2024, Dean Rasheed committed patch:

Add support for MERGE ... WHEN NOT MATCHED BY SOURCE.
 
This allows MERGE commands to include WHEN NOT MATCHED BY SOURCE
actions, which operate on rows that exist in the target relation, but
not in the data source. These actions can execute UPDATE, DELETE, or
DO NOTHING sub-commands.
 
This is in contrast to already-supported WHEN NOT MATCHED actions,
which operate on rows that exist in the data source, but not in the
target relation. To make this distinction clearer, such actions may
now be written as WHEN NOT MATCHED BY TARGET.
 
Writing WHEN NOT MATCHED without specifying BY SOURCE or BY TARGET is
equivalent to writing WHEN NOT MATCHED BY TARGET.
 
Dean Rasheed, reviewed by Alvaro Herrera, Ted Yu and Vik Fearing.
 
Discussion: https://postgr.es/m/CAEZATCWqnKGc57Y_JanUBHQXNKcXd7r=0R4NEZUVwP+syRkWbA@mail.gmail.com

Continue reading Waiting for PostgreSQL 17 – Add support for MERGE … WHEN NOT MATCHED BY SOURCE.