Hi, On 2022-04-07 21:39:55 -0700, David G. Johnston wrote: > On Thu, Apr 7, 2022 at 8:59 PM Andres Freund <and...@anarazel.de> wrote: > > > > > <para> > > Cumulative statistics are collected in shared memory. Every > > <productname>PostgreSQL</productname> process collects statistics > > locally > > then updates the shared data at appropriate intervals. When a server, > > including a physical replica, shuts down cleanly, a permanent copy of > > the > > statistics data is stored in the <filename>pg_stat</filename> > > subdirectory, > > so that statistics can be retained across server restarts. In contrast, > > when starting from an unclean shutdown (e.g., after an immediate > > shutdown, > > a server crash, starting from a base backup, and point-in-time > > recovery), > > all statistics counters are reset. > > </para> > > > > I like this. My comment regarding using "i.e.," here stands though.
Argh. I'd used in e.g., but not i.e.. > > > > <para> > > The cumulative statistics system is active during recovery. All scans, > > reads, blocks, index usage, etc., will be recorded normally on the > > standby. However, WAL replay will not increment relation and database > > specific counters. I.e. replay will not increment pg_stat_all_tables > > columns (like n_tup_ins), nor will reads or writes performed by the > > startup process be tracked in the pg_statio views, nor will associated > > pg_stat_database columns be incremented. > > </para> > > > > > I like this too. The second part with three nors is a bit rough. Maybe: Agreed. I tried to come up with a smoother formulation, but didn't (perhaps because I was a tad tired). > ... specific counters. In particular, replay will not increment > pg_stat_database or pg_stat_all_tables columns, and the startup process > will not report reads and writes for the pg_statio views. > > It would helpful to give at least one specific example of what is being > recorded normally, especially since we give three of what is not. The second sentence is a set of examples - or do you mean examples for what actions by the startup process are counted? Greetings, Andres Freund
