LoadError： MySQL2 gem 问题与不正确的 libmysql 客户端.so.20 版本在 Ubuntu LTS 20.04

Question

自从升级到 Ubuntu LTS 20.04（从 LTS 18）以来，我被提升到了更新版本的 MySQL（从 v5.7.3 升级到 8.0.16）。所有数据库和配置都已成功更新，但 MySQL2 Gem 坚持尝试针对较旧版本的 libmysql 客户端（libmysqlclient.so.20 而不是较新的 libmysqlclient.so.21）进行构建。

我已经卸载并重新安装了APT包:mysql-server和libmysqlclient-dev，也卸载并重新安装了MySQL2 gem，但是没有效果。

从下面的数据中可以看出，它似乎仍然错误地链接，我找不到一种方法来使其链接到正确的版本。任何帮助非常感谢。

$ gem list mysql2

*** LOCAL GEMS ***

mysql2 (0.5.3)

$ mysql -v -u *** -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 14
Server version: 8.0.21-0ubuntu0.20.04.4 (Ubuntu)

$ RAILS_ENV=production bundle exec rails c
Traceback (most recent call last):
     1: from /home/**/**/shared/bundle/ruby/2.6.0/gems/mysql2-0.5.3/lib/mysql2.rb:36:in `<top (required)>'
/home/rails/kwai/shared/bundle/ruby/2.6.0/gems/mysql2-0.5.3/lib/mysql2.rb:36:in `require': libmysqlclient.so.20: cannot open shared object file: No such file or directory - /home/rails/kwai/shared/bundle/ruby/2.6.0/gems/mysql2-0.5.3/lib/mysql2/mysql2.so (LoadError)

$ ldd mysql2.so
    linux-vdso.so.1 (0x00007fffa3b5e000)
    libruby.so.2.6 => /home/***/.rvm/rubies/ruby-2.6.3/lib/libruby.so.2.6 (0x00007f8d4c92d000)
    libmysqlclient.so.20 => not found
    libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f8d4c902000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f8d4c710000)
    libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f8d4c6f4000)
    librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f8d4c6e9000)
    libgmp.so.10 => /usr/lib/x86_64-linux-gnu/libgmp.so.10 (0x00007f8d4c663000)
    libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f8d4c65d000)
    libcrypt.so.1 => /lib/x86_64-linux-gnu/libcrypt.so.1 (0x00007f8d4c622000)
    libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f8d4c4d3000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f8d4cecc000)

$ ls -l /usr/lib/x86_64-linux-gnu/libmy*
-rw-r--r-- 1 root root 9242056 Aug  4 12:39 /usr/lib/x86_64-linux-gnu/libmysqlclient.a
lrwxrwxrwx 1 root root      20 Aug  4 12:39 /usr/lib/x86_64-linux-gnu/libmysqlclient.so -> libmysqlclient.so.21
lrwxrwxrwx 1 root root      25 Aug  4 12:39 /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21 -> libmysqlclient.so.21.1.21
-rw-r--r-- 1 root root 7264264 Aug  4 12:39 /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.21

Answer 1

终于解决了。我必须手动删除所有builder和.rvm文件夹中的gem的所有以前副本，然后gem看起来编译正常，一切都恢复正常。

Answer 2

我删除了

./vendor/bundle/ruby/2.7.0/specifications/mysql2-0.5.3.gemspec
./vendor/bundle/ruby/2.7.0/gems/mysql2-0.5.3
./vendor/bundle/ruby/2.7.0/gems/mysql2-0.5.3/lib/mysql2

很管用谢谢