What is the difference between createReadWriteConnection and createSingleConnection?

[dotnetCarpenter]

I'm wondering, what is the minimum required fields in the configuration array? While searching the source code, I came across the read property. I couldn't find anything in the README, so I ask here.

What is the difference between createReadWriteConnection and createSingleConnection?

protected function makeConnection(array $config, $lazy)
{
    if (isset($config['read'])) {
        return $this->createReadWriteConnection($config, $lazy);
    }

    return $this->createSingleConnection($config, $lazy);
}

in ConnectionFactory.php

Just by reading the names. I'm guessing that it's better to leave out read if I only need to make read queries.

[mrjgreen]

This is so you can direct readonly queries to a secondary (replica) server if you have a master / replica set up.

If you look here, it attaches a second connection to the Database object:

https://github.com/mrjgreen/database/blob/master/src/Connectors/ConnectionFactory.php#L140

The Database object uses this connection for selects.