Set MySQL variables via argument in Docker Compose

Question

I'd like to configure the ft_min_word_len and ft_stopword_file settings in my MySQL container. I need shorter words to be indexed as fulltext, and I don't want to use a stopword file at all.

I tried to set the variables with arguments in my docker-compose.yml:

version: "3.4"
services:
  ata-mysql:
    restart: unless-stopped
    image: mysql:5.7.22
    command:
      - "mysqld"
      - "--innodb_buffer_pool_size=400M"
      - "--innodb_buffer_pool_instances=1"
      - "--ft_min_word_len=1"
      - "--ft_stopword_file=''"

But after a restart, it looks like MySQL hasn't picked up this configuration:

mysql> show variables like 'ft_min_word_len';
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| ft_min_word_len | 4     |
+-----------------+-------+
1 row in set (0.00 sec)

mysql> show variables like 'ft_stopword_file';
+------------------+------------+
| Variable_name    | Value      |
+------------------+------------+
| ft_stopword_file | (built-in) |
+------------------+------------+
1 row in set (0.01 sec)

Is it possible to set those variables through an argument? I'd like to avoid creating a separate Dockerfile for this kind of configuration.

Use a read-only volume to a custom my.cnf in your docker-compose.yml — mehrdadep
– mehrdadep, Commented Jan 2, 2021 at 9:54

23tux · Accepted Answer · 2021-01-11 10:55:40Z

5

It turns out, the command line format for this options uses dashes, and not underscores.

So, the settings must look like this

version: "3.4"
services:
  ata-mysql:
    restart: unless-stopped
    image: mysql:5.7.22
    command:
      - "mysqld"
      - "--innodb_buffer_pool_size=400M"
      - "--ft-min_word-len=1"
      - "--ft-stopword-file=''"

Important: Only after I dropped and re-added the index, the settings took effect.

BTW: For InnoDB these two options are --innodb-ft-min-token-size and --innodb-ft-enable-stopword

edited Jan 11, 2021 at 10:55

answered Jan 11, 2021 at 10:46

23tux

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Comments

Dadberg · Accepted Answer · 2021-01-03 02:22:39Z

-1

Well, you're making it harder on yourself by avoiding Dockerfile ENV parameters or my.cnf file methods.

The problem with your setup is that each line within the array will be handled as a separated command like "mysqld" then "--innodb_buffer_pool_size=400M" and so on, which causes the unexpected behavior.

The correct way is to apply the command in your docker-compose.yml as a one line command like this:

version: "3.4"
services:
  data-mysql:
    restart: unless-stopped
    image: mysql:5.7.22
    command:
      - "mysqld --innodb_buffer_pool_size=400M --innodb_buffer_pool_instances=1 --ft_min_word_len=1 --ft_stopword_file=''"

Or you may use the docker compose environment option like this:

version: "3.4"
services:
  data-mysql:
    environment:
      - EXAMPLE=EXAMPLE
      - EXAMPLE=EXAMPLE
      - EXAMPLE=EXAMPLE

And you can get the list of MYSQL ENV from here: https://dev.mysql.com/doc/refman/5.7/en/environment-variables.html

answered Jan 3, 2021 at 2:22

Dadberg

11 silver badge

1 Comment

23tux Over a year ago

I don't think that's true, you can write a command as an array, see github.com/compose-spec/compose-spec/blob/master/… And because YAML parses multiple lines with a leading - as an array, this works. I can confirm this by looking at the actual command. docker ps --no-trunc shows me the following command:

"docker-entrypoint.sh mysqld --innodb_buffer_pool_size=400M --innodb_buffer_pool_instances=1 --ft_min_word_len=1 --ft_stopword_file=''"

Unfortantely, the MYSQL ENV Variables don't include settings for the fulltext index.

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