pgsql: Count pages set all-visible and all-frozen in VM during vacuum

Count pages set all-visible and all-frozen in VM during vacuum

Heap vacuum already counts and logs pages with newly frozen tuples. Now
count and log the number of pages newly set all-visible and all-frozen
in the visibility map.

Pages that are all-visible but not all-frozen are debt for future
aggressive vacuums. The counts of newly all-visible and all-frozen pages
give us insight into the rate at which this debt is being accrued and
paid down.

Author: Melanie Plageman
Reviewed-by: Masahiko Sawada, Alastair Turner, Nitin Jadhav, Andres Freund, Bilal Yavuz, Tomas Vondra
Discussion:
https://postgr.es/m/flat/CAAKRu_ZQe26xdvAqo4weHLR%3DivQ8J4xrSfDDD8uXnh-O-6P6Lg%40mail.gmail.com#6d8d2b4219394f774889509bf3bdc13d,
https://postgr.es/m/ctdjzroezaxmiyah3gwbwm67defsrwj2b5fpfs4ku6msfpxeia%40mwjyqlhwr2wu

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/dc6acfd910b868351f115382fd92f95e5345992c

Modified Files
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src/backend/access/heap/vacuumlazy.c | 123 +++++++++++++++++++++++++++++++----
1 file changed, 111 insertions(+), 12 deletions(-)