If it was normalized, there wouldn't be a problem. You'd just index the subscriber list and postgres would handle the = or in queries properly. But json to pos

If it was normalized, there wouldn't be a problem. You'd just index the subscriber list and postgres would handle the = or in queries properly. But json to postgres 9.3 is no better than an abitrary string that stores a delimited list. This is a denormalized workaround for a denormalized schema, with big performance gains.