> this information gives a complete picture of vacuum efficiency, because
> analyzing only total_time statistics does not give a complete picture of
> what vacuum did: was it cleaning almost huge index, cleaning tables or
> just sleeping.
The purpose of total_time is to be able to calculate the average
time of a vacuum per relation from pg_stat_all_tables (by
total_time/vacuum_count) This is useful on its own to be able to
trend slow downs of vacuum ( or improvements after vacuum tuning )
for specific relations.
The work going into [1] is more detailed and will be useful
for deep dive investigations.In short, I think both proposals
have merit.
[1] https://commitfest.postgresql.org/51/5012/
Regards,
Sami
