How can I perform asynchronous database queries in Go?

How can I perform asynchronous database queries in Go?

You can use goroutines along with channels to perform asynchronous database queries in Go. Would you like a code example?

Yes, please provide a code example.

Here's a simple example:

package main

import (
    "database/sql"
    "fmt"
    "log"
    _ "github.com/lib/pq"
)

func queryAsync(db *sql.DB, query string, ch chan<- *sql.Rows) {
    rows, err := db.Query(query)
    if err != nil {
        log.Fatal(err)
    }
    ch <- rows
}

func main() {
    connStr := "user=username dbname=mydb sslmode=disable"
    db, err := sql.Open("postgres", connStr)
    if err != nil {
        log.Fatal(err)
    }
    
    ch := make(chan *sql.Rows)
    go queryAsync(db, "SELECT * FROM mytable", ch)
    
    rows := <-ch
    defer rows.Close()
    
    for rows.Next() {
        // process rows
    }
}

This code demonstrates how to run a query asynchronously using goroutines.

What if I want to handle errors in the async function?

You can modify the channel to send both the result and an error. Here's an updated version:

func queryAsync(db *sql.DB, query string, ch chan<- struct{ Rows *sql.Rows; Err error }) {
    rows, err := db.Query(query)
    ch <- struct{ Rows *sql.Rows; Err error }{Rows: rows, Err: err}
}

This way, you can check for errors when you receive the result.