$re = '/factType=(?<facttype>\w+).(?<params>.+)/m';
$str = 'msg: abc.asia - [2021-08-23T00:27:08.152+0000] "GET /facts?factType=COMMERCIAL&sourceSystem=ADMIN&sourceOwner=ABC&filters=%257B%2522stringMatchFilters%2522:%255B%257B%2522key%2522:%2522BFEESCE((json_data-%253E%253E\'isNotSearchable\')::boolean,%2520false)%2522,%2522value%2522:%2522false%2522,%2522operator%2522:%2522EQ%2522%257D%255D,%2522multiStringMatchFilters%2522:%255B%257B%2522key%2522:%2522json_data-%253E%253E\'id\'%2522,%2522values%2522:%255B%25224970111%2522%255D%257D%255D,%2522containmentFilters%2522:%255B%255D,%2522nestedMultiStringMatchFilter%2522:%255B%255D,%2522nestedStringMatchFilters%2522:%255B%255D%257D&sorts=%257B%2522sortOrders%2522:%255B%257B%2522key%2522:%2522id%2522,%2522order%2522:%2522DESC%2522%257D%255D%257D&pagination=null';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php