<?php

$db = new PDO('sqlite:locktest.sq3');
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$sql = array(
	'CREATE TABLE IF NOT EXISTS locktest (item TEXT UNIQUE)',
);

foreach($sql as $line) $db->exec($line);

$insert = $db->prepare("INSERT OR REPLACE INTO locktest (item) VALUES (?)");
$select = $db->prepare("SELECT COUNT(*) FROM locktest");

while(true) {
	$db->beginTransaction();
	echo "Got lock\n";
	
	$end = microtime(true) + rand(2, 3);
	while(microtime(true) < $end) {
		// uncomment these two lines for failure
		#$select->execute();
		#$data = $select->fetchAll();
	
		$insert->execute(array(rand(0,1000)));
		
		$select->execute();
		$data = $select->fetchAll();
	}
	
	$db->commit();
	echo "Released lock\n";
	
	// if we dont sleep then the race winner holds the lock until it exits while the other blocks
	usleep(100000);
	
	
}