# Configuring Ecto repository stats

This guide covers how to configure the LiveDashboard to show stats from your underlying database. These stats are shown for Ecto repositories running on `Ecto.Adapters.Postgres`, `Ecto.Adapters.MyXQL`, or `Ecto.Adapters.SQLite3`. You can also [override the info module](#overriding-the-info-module) used for a repository — for example, for a PostgreSQL-compatible database that needs different queries.

## Installing Ecto Stats

### PostgreSQL

To enable the "Ecto Stats" functionality for PostgreSQL in your dashboard, you will need to do the three steps below:

  1. Add the [`ecto_psql_extras`](https://hexdocs.pm/ecto_psql_extras) dependency
  2. (optional) Configure the dashboard
  3. (optional) Install custom PostgreSQL extensions

#### Add the `ecto_psql_extras` dependency

In your `mix.exs`, add the following to your `deps`:

```elixir
  {:ecto_psql_extras, "~> 0.6"},
```

### MySQL/MariaDB

To enable the "Ecto Stats" functionality for MySQL or MariaDB in your dashboard, you will need to do the three steps below:

  1. Add the [`ecto_mysql_extras`](https://hexdocs.pm/ecto_mysql_extras) dependency
  2. (optional) Configure the dashboard
  3. (optional) MySQL/MariaDB configuration

#### Add the `ecto_mysql_extras` dependency

In your `mix.exs`, add the following to your `deps`:

```elixir
  {:ecto_mysql_extras, "~> 0.3"},
```

### SQLite

To enable the "Ecto Stats" functionality for SQLite in your dashboard, you will need to do the three steps below:

  1. Add the [`ecto_sqlite3_extras`](https://hexdocs.pm/ecto_sqlite3_extras) dependency
  2. (optional) Configure the dashboard

#### Add the `ecto_sqlite3_extras` dependency

In your `mix.exs`, add the following to your `deps`:

```elixir
  {:ecto_sqlite3_extras, "~> 1.2.0"},
```

### Configure the dashboard

This step is **only needed if you want to restrict the repositories** listed in your dashboard, because
by default all _repos_ are going to be listed.

Go to the `live_dashboard` call in your router and list your repositories:

```elixir
live_dashboard "/dashboard", ecto_repos: [MyApp.Repo]
```

You want to list all repositories that connect to distinct databases. For example, if you have both `MyApp.Repo` and `MyApp.RepoAnother` but they connect to the same database, there is no benefit in listing both. Repositories running on `Ecto.Adapters.Postgres`, `Ecto.Adapters.MyXQL`, or `Ecto.Adapters.SQLite3` are detected automatically. To customize the queries used for a repository, see [Overriding the info module](#overriding-the-info-module).

If you want to disable the "Ecto Stats" option altogether, set `ecto_repos: []`.

Some queries such as `long_running_queries` can be configured by passing an extra `ecto_psql_extras_options` for PostgreSQL or `ecto_mysql_extras_options` for MySQL/MariaDB,
which is a keyword where:

- each key is the name of the query
- each value is itself a keyword to be passed as `args`

For example, if you want to configure the threshold for `long_running_queries`:

#### PostgreSQL example

```elixir
live_dashboard "/dashboard",
  ecto_repos: [MyApp.Repo],
  ecto_psql_extras_options: [long_running_queries: [threshold: "200 milliseconds"]]
```

See the [`ecto_psql_extras` documentation](https://hexdocs.pm/ecto_psql_extras/readme.html#usage) for available options.

#### MySQL/MariaDB example

```elixir
live_dashboard "/dashboard",
  ecto_repos: [MyApp.Repo],
  ecto_mysql_extras_options: [long_running_queries: [threshold: 200]]
```

See the [`ecto_mysql_extras` documentation](https://hexdocs.pm/ecto_mysql_extras/readme.html#usage) for available options.

#### SQLite example

```elixir
live_dashboard "/dashboard",
  ecto_repos: [MyApp.Repo],
  ecto_sqlite3_extras_options: []
```

See the [`ecto_sqlite3_extras` documentation](https://github.com/orsinium-labs/ecto_sqlite3_extras) for available options.

### Overriding the info module

By default, the module used to load the stats — the "info module" — is inferred from each repository's adapter:

- `Ecto.Adapters.Postgres` uses `EctoPSQLExtras`
- `Ecto.Adapters.MyXQL` uses `EctoMySQLExtras`
- `Ecto.Adapters.SQLite3` uses `EctoSQLite3Extras`

You can override this by listing a repository as a `{repo, info_module}` tuple instead of a bare module:

```elixir
live_dashboard "/dashboard",
  ecto_repos: [MyApp.Repo, {MyApp.CompatRepo, MyApp.CompatExtras}]
```

This is useful for a PostgreSQL-compatible database that runs on `Ecto.Adapters.Postgres` — and so is detected as `EctoPSQLExtras` — but needs a different set of queries. You can point it at an info module with queries tailored to that database instead. The given `info_module` must implement the same API as `EctoPSQLExtras`, `EctoMySQLExtras`, and `EctoSQLite3Extras`.

### Install custom PostgreSQL extensions

Once the repository page is enabled, some of the queries (Calls and Outliers) require the [pg_stat_statements](https://www.postgresql.org/docs/current/pgstatstatements.html) extension to be installed. If you wish to access said functionality, you must install the extension first, otherwise said functionality won't be shown.

### MySQL/MariaDB configuration

The user which is accessing the repo should have access to the certain system level databases. See the [`ecto_mysql_extras` documentation](https://hexdocs.pm/ecto_mysql_extras/readme.html#mysql-mariadb-configuration) for more details which schemas are being used.

For MariaDB the `performance_schema` isn't enabled by default. To enable this add `performance_schema=ON` to `my.cnf`. These changes take effect after a restart. See the [`ecto_mysql_extras` documentation](https://hexdocs.pm/ecto_mysql_extras/readme.html#performance-schema) for more details.