Incremental View Maintenance, take 2

Hello hackers,

Here's a rebased version of the patch-set adding Incremental View
Maintenance support for PostgreSQL. That was discussed in [1].

The patch-set consists of the following eleven patches. 

- 0001: Add a syntax to create Incrementally Maintainable Materialized Views
- 0002: Add relisivm column to pg_class system catalog
- 0003: Allow to prolong life span of transition tables until transaction end
- 0004: Add Incremental View Maintenance support to pg_dum
- 0005: Add Incremental View Maintenance support to psql
- 0006: Add Incremental View Maintenance support
- 0007: Add DISTINCT support for IVM
- 0008: Add aggregates support in IVM
- 0009: Add support for min/max aggregates for IVM
- 0010: regression tests
- 0011: documentation

[1] https://www.postgresql.org/message-id/flat/20181227215726.4d166b4874f8983a641123f5%40sraoss.co.jp


Regards,
Yugo Nagata

-- 
Yugo NAGATA <nagata@sraoss.co.jp>