Author: depesz

Waiting for PostgreSQL 17 – ALTER TABLE command to change generation expression

On 4th of January 2024, Peter Eisentraut committed patch:

ALTER TABLE command to change generation expression
 
This adds a new ALTER TABLE subcommand ALTER COLUMN ... SET EXPRESSION
that changes the generation expression of a generated column.
 
The syntax is not standard but was adapted from other SQL
implementations.
 
This command causes a table rewrite, using the usual ALTER TABLE
mechanisms.  The implementation is similar to and makes use of some of
the infrastructure of the SET DATA TYPE subcommand (for example,
rebuilding constraints and indexes afterwards).  The new command
requires a new pass in AlterTablePass, and the ADD COLUMN pass had to
be moved earlier so that combinations of ADD COLUMN and SET EXPRESSION
can work.
 
Author: Amul Sul <sulamul@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CAAJ_b94yyJeGA-5M951_Lr+KfZokOp-2kXicpmEhi5FXhBeTog@mail.gmail.com

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Waiting for PostgreSQL 17 – Add support for incremental backup.

On 20th of December 2023, Robert Haas committed patch:

Add support for incremental backup.
 
To take an incremental backup, you use the new replication command
UPLOAD_MANIFEST to upload the manifest for the prior backup. This
prior backup could either be a full backup or another incremental
backup.  You then use BASE_BACKUP with the INCREMENTAL option to take
the backup.  pg_basebackup now has an --incremental=PATH_TO_MANIFEST
option to trigger this behavior.
 
An incremental backup is like a regular full backup except that
some relation files are replaced with files with names like
INCREMENTAL.${ORIGINAL_NAME}, and the backup_label file contains
additional lines identifying it as an incremental backup. The new
pg_combinebackup tool can be used to reconstruct a data directory
from a full backup and a series of incremental backups.
 
Patch by me.  Reviewed by Matthias van de Meent, Dilip Kumar, Jakub
Wartak, Peter Eisentraut, and Álvaro Herrera. Thanks especially to
Jakub for incredibly helpful and extensive testing.
 
Discussion: http://postgr.es/m/CA+TgmoYOYZfMCyOXFyC-P+-mdrZqm5pP2N7S-r0z3_402h9rsA@mail.gmail.com

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Waiting for PostgreSQL 17 – Allow \watch queries to stop on minimum rows returned

On 29th of August 2023, Daniel Gustafsson committed patch:

Allow \watch queries to stop on minimum rows returned
 
When running a repeat query with \watch in psql, it can be
helpful to be able to stop the watch process when the query
no longer returns the expected amount of rows.  An example
would be to watch for the presence of a certain event in
pg_stat_activity and stopping when the event is no longer
present, or to watch an index creation and stop when the
index is created.
 
This adds a min_rows=MIN parameter to \watch which can be
set to a non-negative integer, and the watch query will
stop executing when it returns less than MIN rows.
 
Author: Greg Sabino Mullane <htamfids@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/CAKAnmmKStATuddYxP71L+p0DHtp9Rvjze3XRoy0Dyw67VQ45UA@mail.gmail.com

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Waiting for PostgreSQL 17 – Generate new LOG for “trust” connections under log_connections

On 26th of August 2023, Michael Paquier committed patch:

Generate new LOG for "trust" connections under log_connections
 
Adding an extra LOG for connections that have not set an authn ID, like
when the "trust" authentication method is used, is useful for audit
purposes.
 
A couple of TAP tests for SSL and authentication need to be tweaked to
adapt to this new LOG generated, as some scenarios expected no logs but
they now get a hit.
 
Reported-by: Shaun Thomas
Author: Jacob Champion
Reviewed-by: Robert Haas, Michael Paquier
Discussion: https://postgr.es/m/CAFdbL1N7-GF-ZXKaB3XuGA+CkSmnjFvqb8hgjMnDfd+uhL2u-A@mail.gmail.com

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Waiting for PostgreSQL 17 – Add to_bin() and to_oct().

On 23rd of August 2023, Nathan Bossart committed patch:

Add to_bin() and to_oct().
 
This commit introduces functions for converting numbers to their
equivalent binary and octal representations.  Also, the base
conversion code for these functions and to_hex() has been moved to
a common helper function.
 
Co-authored-by: Eric Radman
Reviewed-by: Ian Barwick, Dag Lem, Vignesh C, Tom Lane, Peter Eisentraut, Kirk Wolak, Vik Fearing, John Naylor, Dean Rasheed
Discussion: https://postgr.es/m/Y6IyTQQ/TsD5wnsH%40vm3.eradman.com

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Human/version sort in PostgreSQL

Ever been in situation where you had to sort data that is partially text, and partially numerical?

Like invoice numbers: prefix-9, prefix-10, prefix-11, other-5, other-20 ? Normally you can't do order by as you will get them in wrong order: other-20 ⇒ other-5 ⇒ prefix-10 ⇒ prefix-11 ⇒ prefix-9. Can something be done with it?

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