presto-main/src/main/java/io/prestosql/index/IndexManager.java/IndexManager/getProvider
class IndexManager:    private ConnectorIndexProvider getProvider(IndexHandle handle)
    {
        ConnectorIndexProvider result = providers.get(handle.getCatalogName());
        checkArgument(result != null, "No index provider for connector '%s'", handle.getCatalogName());
        return result;
    }