Materialized views is a feature to store the results of view definition queries in DB in order to achieve faster query response. However, after base relations are modified, view maintenance is needed to keep the contents up to date. REFRESH MATERIALIZED VIEW command is prepared for the purpose, but this has to recompute the contents from a scratch, so this is not efficient in cases where only a small part of a base table is modified. Incremental View Maintenance (IVM) is a technique to maintain materialized views efficiently, which computes and applies only the incremental changes to the materialized views rather than recomputing. This feature is not implemented on PostgreSQL yet. We have proposed a patch to implement IVM on PostgreSQL and this is now under discussion. Since the first submission of the last year, we have made a great progress on this patch. For example, some aggregates, subqueries, self-join, and outer joins are supported now. These operations are important since they are commonly used in real applications. In this talk, we will explain the current status of our IVM implementation. The talk includes what problems are under the implementation, its solutions, what the current implementation can do, and what limitations and problems are left.