> ## Documentation Index
> Fetch the complete documentation index at: https://cubed3-docs-cub-4190.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# MySQL

> Configure Cube’s MySQL client with TCP or Unix socket access, SSL, pooling limits, and optional timezone handling flags.

## Prerequisites

* The hostname for the [MySQL][mysql] database server
* The username/password for the [MySQL][mysql] database server
* The name of the database to use within the [MySQL][mysql] database server

## Setup

### Manual

Add the following to a `.env` file in your Cube project:

```dotenv theme={"dark"}
CUBEJS_DB_TYPE=mysql
CUBEJS_DB_HOST=my.mysql.host
CUBEJS_DB_NAME=my_mysql_database
CUBEJS_DB_USER=mysql_user
CUBEJS_DB_PASS=**********
```

## Environment Variables

| Environment Variable | Description | Possible Values | Required |
| - | - | - | :-: |
| [`CUBEJS_DB_HOST`](/reference/configuration/environment-variables#cubejs_db_host) | The host URL for a database | A valid database host URL | ✅ |
| [`CUBEJS_DB_SOCKET_PATH`](/reference/configuration/environment-variables#cubejs_db_socket_path) | See [connecting via a Unix socket](#connecting-via-a-unix-socket) | A valid path to a socket | ❌ |
| [`CUBEJS_DB_PORT`](/reference/configuration/environment-variables#cubejs_db_port) | The port for the database connection | A valid port number | ❌ |
| [`CUBEJS_DB_NAME`](/reference/configuration/environment-variables#cubejs_db_name) | The name of the database to connect to | A valid database name | ✅ |
| [`CUBEJS_DB_USER`](/reference/configuration/environment-variables#cubejs_db_user) | The username used to connect to the database | A valid database username | ✅ |
| [`CUBEJS_DB_PASS`](/reference/configuration/environment-variables#cubejs_db_pass) | The password used to connect to the database | A valid database password | ✅ |
| [`CUBEJS_DB_SSL`](/reference/configuration/environment-variables#cubejs_db_ssl) | If `true`, enables SSL encryption for database connections from Cube | `true`, `false` | ❌ |
| [`CUBEJS_DB_MAX_POOL`](/reference/configuration/environment-variables#cubejs_db_max_pool) | The maximum number of concurrent database connections to pool. Default is `8` | A valid number | ❌ |
| [`CUBEJS_DB_MYSQL_USE_NAMED_TIMEZONES`](/reference/configuration/environment-variables#cubejs_db_mysql_use_named_timezones) | The flag to use time zone names or numeric offsets for time zone conversion. Default is `false` | `true`, `false` | ❌ |
| [`CUBEJS_CONCURRENCY`](/reference/configuration/environment-variables#cubejs_concurrency) | The number of [concurrent queries][ref-data-source-concurrency] to the data source | A valid number | ❌ |

[ref-data-source-concurrency]: /admin/connect-to-data/concurrency#data-source-concurrency

## Pre-Aggregation Feature Support

### count\_distinct\_approx

Measures of type
[`count_distinct_approx`][ref-schema-ref-types-formats-countdistinctapprox] can
not be used in pre-aggregations when using MySQL as a source database.

## Pre-Aggregation Build Strategies

<Info>
  To learn more about pre-aggregation build strategies, [head
  here][ref-caching-using-preaggs-build-strats].
</Info>

| Feature | Works with read-only mode? | Is default? |
| - | :-: | :-: |
| Batching | ✅ | ✅ |
| Export Bucket | - | - |

By default, MySQL uses [batching][self-preaggs-batching] to build
pre-aggregations.

### Batching

No extra configuration is required to configure batching for MySQL.

### Export Bucket

MySQL does not support export buckets.

## SSL

To enable SSL-encrypted connections between Cube and MySQL, set the
[`CUBEJS_DB_SSL`](/reference/configuration/environment-variables#cubejs_db_ssl) environment variable to `true`. For more information on how to
configure custom certificates, please check out [Enable SSL Connections to the
Database][ref-recipe-enable-ssl].

## Additional configuration

### Connecting via a Unix socket

To connect to a local MySQL database using a Unix socket, use the
[`CUBEJS_DB_SOCKET_PATH`](/reference/configuration/environment-variables#cubejs_db_socket_path) environment variable, for example:

```dotenv theme={"dark"}
CUBEJS_DB_SOCKET_PATH=/var/run/mysqld/mysqld.sock
```

When doing so, [`CUBEJS_DB_HOST`](/reference/configuration/environment-variables#cubejs_db_host) will be ignored.

### Connecting to MySQL 8

MySQL 8 uses a new default authentication plugin (`caching_sha2_password`)
whereas previous version used `mysql_native_password`. Please
[see this answer on StackOverflow](https://stackoverflow.com/a/50377944)
for a workaround.

<Info>
  For additional details, check the [relevant issue](https://github.com/cube-js/cube/issues/3525) on GitHub.
</Info>

[mysql]: https://www.mysql.com/

[ref-caching-using-preaggs-build-strats]: /docs/pre-aggregations/using-pre-aggregations#pre-aggregation-build-strategies

[ref-recipe-enable-ssl]: /recipes/configuration/using-ssl-connections-to-data-source

[ref-schema-ref-types-formats-countdistinctapprox]: /reference/data-modeling/measures#type

[self-preaggs-batching]: #batching