Provides the connection pool for asynchronous SQLx connections.

Opening a database connection for each and every operation to the database can quickly become expensive. Furthermore, sharing a database connection between threads and functions can be difficult to express in Rust.

A connection pool is a standard technique that can manage opening and re-using connections. Normally it also enforces a maximum number of connections as these are an expensive resource on the database server.

SQLx provides a canonical connection pool implementation intended to satisfy the majority of use cases.

See [Pool][crate::pool::Pool] for details.

Type aliases are provided for each database to make it easier to sprinkle Pool through your codebase:

• [MssqlPool][crate::mssql::MssqlPool] (MSSQL)
• [MySqlPool][crate::mysql::MySqlPool] (MySQL)
• [PgPool][crate::postgres::PgPool] (PostgreSQL)
• [SqlitePool][crate::sqlite::SqlitePool] (SQLite)

Opening a connection pool

A new connection pool with a default configuration can be created by supplying Pool with the database driver and a connection string.

use sqlx::Pool;
use sqlx::postgres::Postgres;

let pool = Pool::<Postgres>::connect("postgres://").await?;

For convenience, database-specific type aliases are provided:

use sqlx::mssql::MssqlPool;

let pool = MssqlPool::connect("mssql://").await?;

Using a connection pool

A connection pool implements [Executor][crate::executor::Executor] and can be used directly when executing a query. Notice that only an immutable reference (&Pool) is needed.

sqlx::query("DELETE FROM articles").execute(&pool).await?;

A connection or transaction may also be manually acquired with [Pool::acquire] or [Pool::begin].