utf8mb4 处的 MySQL 5.7 character_set_client 堆栈

Question

Long story short: we have a PHP-based self-developed CMS, originally on PHP5.x and MySQL, using a healthy combination of utf8 and iso-8859-1 char-sets (don't judge, I know it's weird but it's working). On our production environment our server provider upgraded to PHP7.2 and (after a few weeks of refactoring) everything works just fine.

Parallel to this production environment I've set up (or at least I tried to) a test environment for our development, VirtualBox Ubuntu 20.04, apache2.4, PHP7.2 and MySQL5.7.

in /etc/php/7.2/apache2/php.ini I have:

default_charset = "iso-8859-1"

in /etc/mysql/my.cnf I have:

[client]
default-character-set   = utf8


[mysqld_safe]
default-character-set   = utf8

[mysql]
default-character-set   = utf8


[mysqld]
init_connect                   = 'SET NAMES utf8'
character-set-client-handshake = false #force encoding to uft8
character-set-server           = utf8
collation-server               = utf8_unicode_ci

Now, on our development server the character_set_client=utf8mb4 and character_set_results=utf8mb4 and I can't find a way to change it.

The problem is, that when I try to import on our development server dumps from our production server (through our CMS), or when I try to save texts with special characters like ü or ä it always cuts the word at the occurrence and saves only the rest, eg instead of chüd will save only ch or instead of einträge it saves only eintr .

However I can save ü manually in DB without a problem (don't have to use ü )

(we have a second development server, Ubuntu 14.04, apache2.4, PHP5.6, MySQL5.7 and basically the same settings as on PHP7.2 testserver, and everything works fine)

Maybe PHP7.2 is doing the mess here, I am really out of ideas.

Any help will be appreciated. Thank you

Answer 1

See "truncation" in Trouble with UTF-8 characters; what I see is not what I stored

I wonder if having apache not set to UTF-8 messes up <form>s .

init_connect = 'SET NAMES utf8' sets 3 CHARACTER_SET_% values if you are not connecting as "root" . So, change it to utf8mb4 and do not connect as "root".

Are you sure about the encoding in the imported data? (I suspect this causes the truncation problem.) Can you get a hex dump of a small portion of the data.

For Western European languages, MySQL's utf8 and utf8mb4 work the same. That is, the init_connect that you have should be adequate _if the incoming data is really UTF-8, not iso...

For reference here are hex values:

char latin1 utf8
ä    E4     C3A4
ü    FC     C3BC