Moving data Postgres to MySQL using PHP/Laravel5 - php

Question

I'm using:
A local Postgres DB
Laravel 5 with a MySQL DB also local
Postgres DB contains the table structure from OTRS - with over 91.000 rows on the table "tickets"
I needed to move the data from one DB to the other. What I did was compile a big query that united all the data I needed and run it in a PHP script I created inside the Laravel structure. Then I iterated through the results using Eloquent to insert into MySQL. I know it's terrible but I had to remove the memory and time limits for PHP in order to do this and though it took a really long time, it worked!
Right now I realized I missed something, I need to rerun a similar query (results in the same number of rows), but this time to just add one field on the MySQL DB.
My question is, how can I optimize this process? I'm thinking of using chunks but I don't know how to that.
To clarify:
MySql's Tickets table contains 91397 rows and 5 columns
Postgres Tickets table also has 91397 rows and 6 columns
I created a migration on Laravel (MySQL) that added the extra column (though it's empty)
It's probably easier if I show you the code I have.
link

Answer 1

You can use eloquent to do this. Here's how I'd do (untested, may need some tuning):
Set up both DB connections in the config\database.php.
Make two models for the same resource (you can use only one model but I rather not), I'll name them M1 and M2, with different connection attribute. To do this create an attribute inside the model: protected $connection = 'connection_name'.
So basically:
class M1 extends Model {
protected $connection = 'connection_name';
protected $table = 'table_name';
protected $guarded = [];
Same for M2 with a different $connection.
Now in your controller method or wherever you're executing your code, you can chunk queries using eloquent:
//assuming you are transferring M1's db to M2's
M1::chunk(200, function($m1s) //if you wanna use only one model, this should be M1::on('connection-name')->chunk(...
{
foreach ($m1s as $m1)
{
$m2 = new M2();
//this does not copy model-specific attributes like $connection
$m2->fill( $m1->getAttributes() );
$m2->save();
}
});
I think this does the job, can you test this?