Category: DB

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Invalid table or database name mysql.sock


In a development Docker setup, I needed to upgrade the MySQL database from version 5.6 to version 8. The data was stored as a Docker volume in a data directory. After the update, I encountered the following error:

my_db.mysql      | 2024-08-16T09:40:21.463770Z 2 [ERROR] [MY-010520] [Server] Invalid (old?) table or database name 'mysql.sock'
my_db.mysql      | 2024-08-16T09:40:21.468287Z 2 [ERROR] [MY-010784] [Server] Failed to open dir /var/lib/mysql/mysql.sock

Apparently, MySQL 8 treats every file or directory in the data directory as a database table, whereas in the previous version, MySQL 5, only directories were recognized as database tables.

As the the changelog of MySql 8 states:

Because the data dictionary provides information about database objects, the server no longer checks directory names in the data directory to find databases. Consequently, the --ignore-db-dir option and ignore_db_dirs system variable are extraneous and have been removed. Update system configurations and application programs accordingly.

As a result, all files in the data directory volume, in addition to the directories, are mistakenly recognized as database tables–for example, the mysql.sock file, which is created by Docker.

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Import data into MySql with docker-compose

Having a docker-compose setup which involves a Database like Mysql or MariaDB, then at some point you might want to import data into those Databases.

There are several ways to import the data in your docker-compose setup.

  1. Using a volume for import data
  2. Using mysql client from commandline with docker-compose exec
  3. Using phpmyadmin in docker-compose setup
  4. Using a mysql GUI client on the host and connect to the DB in the Docker container

So let’s see how we can do this:

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Migrating user table from Mysql to Postgres with Symfony and Doctrine

When using bin/console make:entity on Mysql and then later you switch your application to Postgres and you have a table called user, which you most likely have when using security component of Symfony.
Then you will receive an error because user is a reserved word in Postgres!

An exception occurred while executing 'INSERT INTO user (id, email, roles, password, is_verified) VALUES (?, ?, ?, ?, ?)' with params [3, "dev@dev.de", "[]", "your-encrypted-password", 0]:
SQLSTATE[42601]: Syntax error: 7 ERROR: syntax error at or near "user"
LINE 1: INSERT INTO user (id, email, roles, password, is_verified) V...

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Docker-compose and Unknown MySQL server host

In case you encounter this error with mysql and your docker-compose setup:

Unknown MySQL server host <mysql-service-name>Code language: HTML, XML (xml)

… and you dont know why because everything seems to be correct.

Then you might have an upgrade problem with mysql because you are reusing an old volume that was created for another mysql version.
This can happen when you use a unspecified tag as mysql:latest (not recommended anyway) and there was a version bump in the official mysql image.
Or you upgraded the mysql container yourself, f.e. from mysql:5.6 to mysql:5.7 and you are reusing the data volume with the mysql files.

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Adminer for Sqlite in Docker

Recently i wanted to use Sqlite with Adminer in Docker and it turned out to be not so easy.
I actually thought i could just declare Adminer in a docker-compose.yml file with a volume mounted, similar as i would do for adminer with mysql.

Update: Today i would rather use the IntelliJ Database Tool for Sqlite administration.

But since Adminer is a popular hacking target they introduced a feature that does not allow to run adminer without a password, out of the box.
Sqlite database usually runs without password and dang, workaround needed!

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Silex and MongoDB simply

Using MongoDB in your Silex Project is quite easy.

I will show this with my Superleansilexplate and will integrate it there as an example.
Since i dont want to integrate MongoDB in Superleansilexplate it will just become an additional gist.

Given you have some smaller amount of data like a counter that needs to be stored or other loose coupled datasets, we simply speak to MongoDB “directly” and store the data via Doctrine MongoDB Abstraction Layer.
Since i presume the Data / Document Structure isnt that complex we dont use Doctrine MongoDB ODM (the Object Document Mapper).
If you want to use it instead, try this Silex Extensions.

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Migrate to Mongolab

Recently i ran into RAM troubles on my vserver for some reasons, i encountered the evil:

Cannot allocate memory at ...

So first i suspected mongodb to use up loads of memory as top showed.

But after some recherche work i learned mongodb only -seems- to use a lot of memory.
see here and here and here
The actual usage was around 20mb RAM, so mongodb was innocent.

The true RAM monsters were some apache and php-fpm zombies, but thats another story.

While suspecting mongodb i thought about outsourcing the mongodb and i found a free and sufficient offer in mongolab.
My interests were on and i gave it a try.
The free version has a limit for up to 240MB storage and since my app is just a small counter it should last for some time.
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Grouping & Sorting in MongoDB

Will man mit PHP und MongoDB soetwas wie “SQL Aggregate Functions” umsetzen muss man sich etwas verbiegen.

MongoDb hat zwar eine group() function, die in etwa SQLs GROUP BY entspricht, allerdings kann man dies nicht kombinieren mit SORT oder LIMIT bzw den sort() und limit() Funktionen, da diese keinen Cursor zurückgibt sondern direkt ein Array.

Will man also sortieren und limitieren muss man sich des Map / Reduce features von MongoDB bedienen.

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