docs/reference/online-stores/mysql.md
The MySQL online store provides support for materializing feature values into a MySQL database for serving online features.
In order to use this online store, you'll need to run pip install 'feast[mysql]'. You can get started by then running feast init and then setting the feature_store.yaml as described below.
{% code title="feature_store.yaml" %}
project: my_feature_repo
registry: data/registry.db
provider: local
online_store:
type: mysql
host: DB_HOST
port: DB_PORT
database: DB_NAME
user: DB_USERNAME
password: DB_PASSWORD
{% endcode %}
The full set of configuration options is available in MySQLOnlineStoreConfig.
By default, the MySQL online store performs row-by-row insert and commit for each feature record. While this ensures per-record atomicity, it can lead to significant overhead on write operations — especially on distributed SQL databases (for example, TiDB, which is MySQL-compatible and uses a consensus protocol).
To improve writing performance, you can enable batch write mode by setting batch_write to true and batch_size, which executes multiple insert queries in batches and commits them together per batch instead of committing each record individually.
{% code title="feature_store.yaml" %}
project: my_feature_repo
registry: data/registry.db
provider: local
online_store:
type: mysql
host: DB_HOST
port: DB_PORT
database: DB_NAME
user: DB_USERNAME
password: DB_PASSWORD
batch_write: true
batch_size: 100
{% endcode %}
The set of functionality supported by online stores is described in detail here. Below is a matrix indicating which functionality is supported by the Mys online store.
| Mys | |
|---|---|
| write feature values to the online store | yes |
| read feature values from the online store | yes |
| update infrastructure (e.g. tables) in the online store | yes |
| teardown infrastructure (e.g. tables) in the online store | yes |
| generate a plan of infrastructure changes | no |
| support for on-demand transforms | yes |
| readable by Python SDK | yes |
| readable by Java | no |
| readable by Go | no |
| support for entityless feature views | yes |
| support for concurrent writing to the same key | no |
| support for ttl (time to live) at retrieval | no |
| support for deleting expired data | no |
| collocated by feature view | yes |
| collocated by feature service | no |
| collocated by entity key | no |
To compare this set of functionality against other online stores, please see the full functionality matrix.