Re: [WIP]Vertical Clustered Index (columnar store extension) - take2

Hello, Iwata-san.
Hello, everybody involved.

I personally see two most exciting things about VCI.
In short: 1. This is index. 2. It has fresh data.

1. Despite performance and other issues that can be fixed anyway, VCI
has great user API. Index doesn't always mean btree index, it is just a
database structure for faster data retrieval. In case of VCI it is
columnar storage for faster data retrieval. It is clear SQL syntax to
put some columns (not the whole table, we can choose specific columns!)
into columnar storage. Users are aware of the fact that indexes can
slow down insertions, no surprises here. No need to change queries,
just add VCI index for some columns that are scanned heavily without
putting the whole table into columnar storage.

2. VCI has own Change Data Capture method. It doesn't use triggers
either logical replication for CDC, it uses IAM and homegrown hooks in
heapam.c. Probably VCI-style CDC could be separated to its own patch
for review and used in other extensions too.

--
Regards,
Timur Magomedov