On Fri, May 31, 2024 at 4:19 AM Andrei Zubkov <zub...@moonset.ru> wrote: > > Hi, > > Th, 30/05/2024 at 10:33 -0700, Alena Rybakina wrote: > > I suggest gathering information about vacuum resource consumption for > > processing indexes and tables and storing it in the table and index > > relationships (for example, PgStat_StatTabEntry structure like it has > > realized for usual statistics). It will allow us to determine how > > well > > the vacuum is configured and evaluate the effect of overhead on the > > system at the strategic level, the vacuum has gathered this > > information > > already, but this valuable information doesn't store it. > > > It seems a little bit unclear to me, so let me explain a little the > point of a proposition. > > As the vacuum process is a backend it has a workload instrumentation. > We have all the basic counters available such as a number of blocks > read, hit and written, time spent on I/O, WAL stats and so on.. Also, > we can easily get some statistics specific to vacuum activity i.e. > number of tuples removed, number of blocks removed, number of VM marks > set and, of course the most important metric - time spent on vacuum > operation.
I've not reviewed the patch closely but it sounds helpful for users. I would like to add a statistic, the high-water mark of memory usage of dead tuple TIDs. Since the amount of memory used by TidStore is hard to predict, I think showing the high-water mark would help users to predict how much memory they set to maintenance_work_mem. Regards, -- Masahiko Sawada Amazon Web Services: https://aws.amazon.com