Practicality and performance of using both pgxpool and sql.DB

[0x071]

I have a project with dependencies where some require sql.DB and others require pgxpool. Currently I instantiate both like this:

pool, err := pgxpool.New(context.Background(), os.Getenv("DATABASE_URL"))
if err != nil {
    return err
}

db, err := stdlib.OpenDBFromPool(pool)
if err != nil {
    return err
}

From here I pass both pool and db to the dependencies that need it. Would there be any issues with this, and how does this work internally? Are there essentially two different connections open?

Based on this discussion it appears that it's okay to to have one pgxpool and one sql.DB instantiated, but I'm not sure about performance. Prior to the new implementation, having a sql.DB created came with a performance cost and other issues, as described here. Is this still the case today?

[jackc]

Are there essentially two different connections open?

No. The sql.DB gets connections as needed from the pgxpool and immediately releases them back to the pgxpool.

Is this still the case today?

It should be fine to use the pgxpool.Pool and the sql.DB created from that pool at the same time. I'm not aware of any performance issues.