In this article, I want to introduce the ICU support in PostgreSQL, which I have worked on for PostgreSQL version 10, to appear later this year.
Sorting is an important functionality of a database system. First, users generally want to see data sorted. Any query result that contains more than one row and is destined for end-user consumption will probably want to be sorted, just for a better user experience. Second, a lot of the internal functionality of a database system depends on sorting data or having sorted data available. B-tree indexes are an obvious example. BRIN indexes have knowledge of order. Range partitioning has to compare values. Merge joins depend on sorted input. The idea that is common to these different techniques is that, roughly speaking, if you have sorted
For PostgreSQL 10, I have worked on a feature called "identity columns". Depesz already wrote a blog post about it and showed that it works pretty much like serial columns:
CREATE TABLE test_old (
id serial PRIMARY KEY,
INSERT INTO test_old (payload) VALUES ('a'), ('b'), ('c') RETURNING *;
CREATE TABLE test_new (
id int GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
INSERT INTO test_new (payload) VALUES ('a'), ('b'), ('c') RETURNING *;
do pretty much the same thing, except that the new way is more verbose. ;-)
So why bother?
The new syntax conforms to the SQL standard. Creating auto-incrementing columns has been a notorious area of incompatibility between different SQL implementations. Some have lately
For a couple of years now a team at 2ndQuadrant led by Andres Freund have been working on adding bi-directional asynchronous multi-master replication support for PostgreSQL. This effort has become known as the BDR project.
We're really excited to see these efforts leading to new PostgreSQL features and have a great deal more still to come.
As a large development project it is neither practical nor desirable to deliver all the changes to PostgreSQL as a single huge patch. That way lies madness and unmaintainable code. It would also be resoundingly rejected by the PostgreSQL community, as it should be.
Instead, BDR has been developed as a series of discrete changes to core PostgreSQL, plus an extension that uses those core changes to implement multi-master