[claar]

It appears work is active (May 2017) in this area, but accent-insensitive collations are still a ways off: https://blog.2ndquadrant.com/icu-support-postgresql-10/

edit: fulafel corrects me below that you can get accent-insensitive collations working using PostgreSQL 10's new ICU collation support. Note that PostgreSQL 10 is currently pre-release.

[fulafel]

That post says that they currently work, but there is a new os-independent collation method coming.

Edit re your edit: the already working collations are in PG 9.x - the OS independent collations are coming in 10.x. (Hence the post title, "More robust collations with ICU support in PostgreSQL 10")

[fauigerzigerk]

But do these "already working" collations include accent-insensitive variants? I didn't think so, and I don't think they are coming in PostgreSQL 10 either. Do you have other information on this?

[petergeoghegan]

They do. The problem is that equality is still strict binary equality for text, for obscure technical reasons. So, while you can get extremely flexible customizations to collation with icu [1], you can't have case insensitive equality, or equality that ignores accents. This is recognized as a problem, and is probably going to be fixed in v11.

[1] https://www.postgresql.org/message-id/CAH2-Wz=bcgmk97YaZ3rs4...

[anarazel]

> The problem is that equality is still strict binary equality for text, for obscure technical reasons

AKA performance.

[fulafel]

My misunderstanding seemed to be that "accent-insensitive" turns out to be a precise technical term from MySQL that says "just sort UTF-8 using the American locale and collation, but pretend accented characters are equal to their non-accented versions" which is not a standard collation order in any locale.

[berns]

I think this is incorrect. In Mysql utf8_spanish_ci and utf8_swedish_ci have different accent rules, for example.

[fulafel]

But then what would be the case for using accent-ignoring spanish collation rules, rather than the default spanish collation rules that sort accented chars according to normal spanish sorting? This sounds strictly inferior in any human facing application.