Sudden error with mariaDB (no implicit conversion of Integer into String)

[wuarmin]

Hello,

I had a working connection to a MariaDB-instance, but suddenly the following error occurs, if I access a relation:

db = Sequel.connect("mysql2://user:passwd@host:3306/mydb", :loggers => [Logger.new($stdout)])
db[:my_table] # here error occurs

TypeError: no implicit conversion of Integer into String
  /home/me/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/sequel-5.52.0/lib/sequel/adapters/shared/mysql.rb:130:in `match'
  /home/me/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/sequel-5.52.0/lib/sequel/adapters/shared/mysql.rb:130:in `server_version'
  /home/me/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/sequel-5.52.0/lib/sequel/adapters/mysql2.rb:81:in `server_version'
  /home/me/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/sequel-5.52.0/lib/sequel/adapters/shared/mysql.rb:796:in `supports_cte?'
  /home/me/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/sequel-5.52.0/lib/sequel/dataset/sql.rb:1545:in `select_with_sql'
  /home/me/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/sequel-5.52.0/lib/sequel/dataset/sql.rb:239:in `select_sql'
  /home/me/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/sequel-5.52.0/lib/sequel/dataset/actions.rb:152:in `each'
  /home/me/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/sequel-5.52.0/lib/sequel/dataset/actions.rb:51:in `block in all'
  /home/me/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/sequel-5.52.0/lib/sequel/dataset/actions.rb:1010:in `_all'
  /home/me/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/sequel-5.52.0/lib/sequel/dataset/actions.rb:51:in `all'
  /home/me/code/tou_etl_jobs/system/boot/telespirit.rb:11:in `block (2 levels) in <top (required)>'

I don't know what the problem is. The code was still working a few days ago.

If I try the following:

db = Sequel.connect("mysql2://user:passwd@host:3306/mydb", :loggers => [Logger.new($stdout)])
columns = db.fetch("SELECT COLUMN_NAME, DATA_TYPE, COLUMN_TYPE FROM INFORMATION_SCHEMA.COLUMNS
 WHERE table_name = 'my_table'").all
ap(columns, indent: -2, index: false)

I get following weird output:

[
  {
    :COLUMN_NAME => 0,
    :DATA_TYPE   => 0,
    :COLUMN_TYPE => 0
  },
  {
    :COLUMN_NAME => 0,
    :DATA_TYPE   => 0,
    :COLUMN_TYPE => 0
  },
  {
    :COLUMN_NAME => 0,
    :DATA_TYPE   => 0,
    :COLUMN_TYPE => 0
  },
  {
    :COLUMN_NAME => 0,
    :DATA_TYPE   => 0,
    :COLUMN_TYPE => 0
  },
  {
    :COLUMN_NAME => 0,
    :DATA_TYPE   => 0,
    :COLUMN_TYPE => 0
  }
]

Maybe someone knows what could be the reason here.

Thanks
-- Armin

[jeremyevans]

Try recompiling the mysql2 gem (gem pristine mysql2), because it looks like something is very wrong at the driver level. You could confirm that by using mysql2 directly and see if you get the same results.

[wuarmin]

Thank you for the fast response Mr. Evans! gem pristine mysql2 did not change the behavior.
The error happens here:

sequel/lib/sequel/adapters/shared/mysql.rb

Line 130 in ace201d

m = /(\d+)\.(\d+)\.(\d+)/.match(fetch('SELECT version()').single_value!)

It seems, that fetch('SELECT version()').single_value! returns the integer 10 instead of the string 10.5.12-MariaDB-0+deb11u1.

[jeremyevans]

For some reason, every data type returned is being treated as integer. Why that is, I have no idea, but it points to something broken at a level below Sequel. Can you replicate this issue in a different environment?

[wuarmin]

Very strange. The error occurs at my dev-env. At my prod-env (same mysql2-get version) it works. Tomorrow I will check, if I can replicate it in another env.

[wuarmin]

I executed this code at dev and prod-env:

client = Mysql2::Client.new(:host => "myhost", :username => "me", :password => "abc123", :database => "mydb")
results = client.query("SELECT version()")
results.each do |row|
  ap row
end

dev-env-output:

{
    "version()" => 10
}

prod-env-output:

{
    "version()" => "10.5.12-MariaDB-0+deb11u1"
}

[wuarmin]

I'm on Ubuntu and had to install libmariadbclient-dev. Before that only libmariadb-dev was installed, as described in the mysql2-docs. But then suddenly the error occurred and that was no longer sufficient, so, as I said, I installed the libmariadbclient-dev-package.

apt-get install libmariadbclient-dev

After that I recompiled the mysql2 gem and now it works 🎆 .

[fnordfish]

Just to add for the next person running into this.
I ran into the same issue with Rockylinux trying to connect to a MariaDB 11.4.
Mysql2 will build against mariadb-devel or mariadb-connector-c but then return only Integer values.

On Rockylinux, I had to use mysql-devel instead

[jeremyevans]

For users having issues with the mysql2 adapter due to underlying driver issues, I recommend trying the trilogy adapter, as the trilogy driver is self-contained and should build the same way regardless of what packages are installed on the system.