从 Apache 服务器到 Mysql 的连接问题

我正在Centos7和Mysql 5.6.46. 我需要将默认 datadir 位置移动到加密分区，并相应地更改了我的默认 /etc/my.cnf 文件：

# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html

[mysqld]
#
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin
#
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
datadir=/NEW_FOLDER/mysql
socket=/NEW_FOLDER/mysql/mysql.sock

# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

# Recommended in standard MySQL setup
#sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES 
sql_mode=""

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

[client]
port=3306
socket=/NEW_FOLDER/mysql/mysql.sock

重新启动后，我验证我可以通过编写连接到 Mysql: mysql -u <USERNAME> -p，没有问题。当我的基于 CGI 的服务器尝试访问数据库时，我的问题与此有关。我收到错误：Error connecting to database: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)这对我来说没有多大意义，因为默认套接字目录已更改。

我查看了 Apache 错误日志，我看到了这个：

DBI connect('testuser:localhost','testdb',...) failed: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2) at /srv/www/TestSite/perl-lib/Database.pm line 31.

我转到第 31 行，我看到了这个：

my $dsn = "DBI:mysql:testdb:localhost";
    $dbh = DBI->connect($dsn, 'testuser', 'testpasswd')
      or throw Portal::DatabaseError("Error connecting to database: $DBI::errstr");

在我看来，Apache 正在尝试访问 Mysql，但它不能mysql.socket从新的默认mysql datadir位置使用。有什么想法该怎么做？