WooCommerce Multilingual & Multicurrency - 504 Gateway Time-out Error When Updating Variations

Overview of the issue

If you are using WooCommerce Multilingual, you may experience a 504 Gateway Time-out error when attempting to update product with variations on your website.

Workaround

Please, make sure of having a full backup of your site before proceeding.

• Open …/woocommerce-multilingual/inc/translation-editor/class-wcml-synchronize-variations-data.php file.
• Look for line 219.
• Change:

  	public function get_variation_id_by_lang( $lang, $original_variation_id ) {
  		return $this->wpdb->get_var(
  			$this->wpdb->prepare(
  				"SELECT post_id FROM {$this->wpdb->postmeta} AS pm
                                          JOIN {$this->wpdb->prefix}icl_translations AS tr ON tr.element_id = pm.post_id
                                          WHERE tr.element_type = 'post_product_variation'
                                            AND tr.language_code = %s
                                            AND pm.meta_key = '_wcml_duplicate_of_variation'
                                            AND pm.meta_value = %d",
  				$lang,
  				$original_variation_id
  			)
  		);
  	}
  

• For:

  	public function get_variation_id_by_lang( $lang, $original_variation_id ) {
  		return apply_filters( 'wpml_object_id', $original_variation_id, 'product_variation', false, $lang );
  	}