ON A RAINY weekday in early spring Málaga is thronged with tourists, clambering over the Moorish castle that overlooks the port, carousing at the pavement bars or queuing for one of half-a-dozen art museums. It wasn’t always thus. Until the turn of the century tourists heading for the resorts of the Costa del Sol shunned what was then a drab former industrial town. Today Málaga, Spain’s sixth city, is booming, powered not just by tourism but also by a burgeoning tech industry. Its economy has outpaced the rest of the Andalucía region for most of the past decade. It is held up by some as a model for other Spanish cities, but some locals fear it may fall victim to its own success.