Faster updates

feed-update-pricing.php

<?php

global $wpdb;

$query = $wpdb->prepare("SELECT post_id, table1.meta_value as sku, table2.meta_value as price ".
    "FROM {$wpdb->postmeta} as table1 ".
    "JOIN {$wpdb->postmeta} as table2 USING (post_id) ".
"WHERE ".
		"table1.meta_key = '_sku'  AND ".
		"table2.meta_key = '_price' ".
"GROUP BY post_id".
		";");

$results = $wpdb->get_results($query);

$file = file_get_contents("feed.json");

$json_array = json_decode($file, true);

$working_array = [];

foreach ( $json_array as $product_data ) {
  $working_array[$product_data['sku']] = [
            'price' => $product_data['rrp']
        ];
}

foreach($results as $product) {
  if(isset($working_array[$product->sku]) && $working_array[$product->sku]['price'] != $product->price)  {
    update_post_meta( $product->post_id, '_price', $working_array[$product->sku]['price'], $product->price );
  }
}