Elasticsearch против MongoDB - Стратегия индексирования

Альтернатива сериализации и уникальности

$test = [
    ['abc','def'],
    ['ghi','jkl'],
    ['mno','pql'],
    ['abc','def'],
    ['ghi','jkl'],
    ['mno','pql'],
];

$result = array_reduce(
    $test,
    function($carry,$item){
        if(!in_array($item,$carry)) {
            array_push($carry,$item);
        }
        return $carry;
    },
    []
);

var_dump($result);

/*
 php unique.php
array(3) {
    [0] =>
        array(2) {
            [0] =>
                string(3) "abc"
            [1] =>
                string(3) "def"
        }
    [1] =>
        array(2) {
            [0] =>
                string(3) "ghi"
            [1] =>
                string(3) "jkl"
        }
    [2] =>
        array(2) {
              [0] =>
                  string(3) "mno"
              [1] =>
                  string(3) "pql"
        }
}

* /