  Irregular data in real-world are usually organized as heterogeneous graphs
(HGs) consisting of multiple types of nodes and edges. To explore useful
knowledge from real-world data, both the large-scale encyclopedic HG datasets
and corresponding effective learning methods are crucial, but haven't been well
investigated. In this paper, we construct a large-scale HG benchmark dataset
named UniKG from Wikidata to facilitate knowledge mining and heterogeneous
graph representation learning. Overall, UniKG contains more than 77 million
multi-attribute entities and 2000 diverse association types, which
significantly surpasses the scale of existing HG datasets. To perform effective
learning on the large-scale UniKG, two key measures are taken, including (i)
the semantic alignment strategy for multi-attribute entities, which projects
the feature description of multi-attribute nodes into a common embedding space
to facilitate node aggregation in a large receptive field; (ii) proposing a
novel plug-and-play anisotropy propagation module (APM) to learn effective
multi-hop anisotropy propagation kernels, which extends methods of large-scale
homogeneous graphs to heterogeneous graphs. These two strategies enable
efficient information propagation among a tremendous number of multi-attribute
entities and meantimes adaptively mine multi-attribute association through the
multi-hop aggregation in large-scale HGs. We set up a node classification task
on our UniKG dataset, and evaluate multiple baseline methods which are
constructed by embedding our APM into large-scale homogenous graph learning
methods. Our UniKG dataset and the baseline codes have been released at
https://github.com/Yide-Qiu/UniKG.
