Re: Add os_page_num to pg_buffercache

The following review has been posted through the commitfest application:
make installcheck-world: tested, passed
Implements feature: tested, passed
Spec compliant: tested, passed
Documentation: tested, passed

Hi Bertrand,

Just tried out your patch, nice work, thought to leave a review as well.

Patch applied successfully on top of commit a27893df4 in master.
Ran the tests in pg_buffercache and they pass including the new ones.

Running "pagesize" on my laptop returns 16384.

test=# SELECT current_setting('block_size');
current_setting
-----------------
8192
(1 row)

Given the above, the results are as expected:

test=# select * from pg_buffercache_os_pages;
bufferid | os_page_num
----------+-------------
1 | 0
2 | 0
3 | 1
4 | 1
5 | 2
6 | 2

I have noticed that pg_buffercache_os_pages would be the 3rd function
which follows the same high-level structure (others being pg_buffercache_pages
and pg_buffercache_numa_pages). I am wondering if this would be let's say
"strike three" - time to consider extracting out a high-level "skeleton" function,
with a couple of slots which would then be provided by the 3 variants.

Kind regards,
Mircea

The new status of this patch is: Waiting on Author