Caught exception: Lost connection to MySQL server during query

UPDATE ps_product p  INNER JOIN ps_multicurrency_product mcp ON  p.id_product = mcp.id_product INNER JOIN ps_currency c ON  mcp.id_currency = c.id_currency SET p.price = mcp.price/c.conversion_rate, p.wholesale_price = mcp.wholesale_price/c.conversion_rate WHERE  mcp.last_update < "2021-01-27 17:54:38"