[rfc] overhauling pgstat.stat

Hi,

I'm considering overhauling pgstat.stat, and would like to know how many
people are interested in this topic.

As you may know, this file could be handreds of MB in size, because
pgstat.stat holds all access statistics in each database, and it needs
to read/write an entire pgstat.stat frequently.

As a result, pgstat.stat often generates massive I/O operation,
particularly when having a large number of tables in the database.

To support multi-tenancy or just a large number of tables (up to 10k
tables in single database), I think pgstat.stat needs to be overhauled.

I think using heap and btree in pgstat.stat would be preferred to reduce
read/write and to allow updating access statistics for specific tables
in pgstat.stat file.

Is this good for us?

Any comments or suggestions?

Regards,
--
Satoshi Nagayasu <snaga(at)uptime(dot)jp>
Uptime Technologies, LLC. http://www.uptime.jp