PHP Open Multiple Connections - php

Question

I would like to run multiple scripts instances of the same script in different browser tabs. And I would like them to have different MySQL connections. Each its unique connection.
I know that mysql_connect has a fourth parameter $new_link which should open a new link, but even that does not open a new connection, usually. Sometimes it does.
I have a XAMPP install on a Widows machine.
The question is: How can I absolutely force PHP/MySQL to open a new connections for each instance of a script? Script runs for about 2mins.
http://localhost/myscript.php
Here are the excerpts of the MySQL code. First load a work assignment from DB and mark it as in progress:
public function loadRange() {
try{
$this->db()->query('START TRANSACTION');
$this->row = $this->db()->getObject("
SELECT * FROM {$this->tableRanges}
WHERE
status = " . self::STATUS_READY_FOR_WORK . "
AND domain_id = {$this->domainId}
ORDER BY sort ASC
LIMIT 1");
if(!$this->row) throw new Exception('Could not load range');
$this->db()->update($this->tableRanges, $this->row->id, array(
'thread_id' => $this->id,
'status' => self::STATUS_WORKING,
'run_name' => $this->runName,
'time_started' => time(),
));
$this->db()->query('COMMIT');
} catch(Exception $e) {
$this->db()->query('ROLLBACK');
throw new Exception($e->getMessage());
}
}
Then the script may or may not INSERT rows in another table based on what it finds.
In the end, when task is finished, the assignment row is UPDATEd again:
$this->db()->update($this->tableRanges, $this->row->id, array(
'status' => self::STATUS_EXECUTED,
'time_finished' => time(),
'count' => $count,
));
In particular, the $this->tableRanges table looks to be locked. Any idea why it is the case? It is an InnoDB table.

Answer 1

I would like to run multiple scripts instances of the same script in different browser tabs. And I would like them to have different MySQL connections. Each its unique connection.
This is actually the case, without any additional effort
The question is: How can I absolutely force PHP/MySQL to open a new connections for each instance of a script.
Answer: do nothing :)

Answer 2

every time you hit http://localhost/myscript.php a new instance is run. Everything about that instance is unique, the web server spawns a new PHP thread, in which all the resources, connections, variables are unique.
Only state management devices such as sessions are shared and that too if you are using different tabs in same browser. If you hit the same URL with different browsers, the state management resources are different too.
To answer your question, like others mentioned before - your connection is different for each instance IF you are using mysql_connect. You could create a persistent connection that does not close when the application exits and reuses it for new connection requests using mysql_pconnect. But in your code it seems you are using the latter and in that case, you are fine.
You can try to set the isolation read level to prevent table stalling while reading for select
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED ;
More information can be found here.
Again I guess it will take a bit of playing around to find which option works the best.