On Sat, Sep 19, 2020 at 1:58 PM Peter Eisentraut <peter.eisentr...@2ndquadrant.com> wrote: > > If I read the code correctly, the VACUUM PARALLEL option is capped by > the active max_parallel_maintenance_workers setting. So if I write > VACUUM (PARALLEL 5), it will still only do 2 by default. Is that > correct?
Yeah, but there is another factor also which is the number of indexes that support parallel vacuum operation. > The documentation (VACUUM man page) seems to indicate a > different behavior. > I think we can change the documentation for parallel option to explain it better. How about: "Perform index vacuum and index cleanup phases of VACUUM in parallel using integer background workers (for the details of each vacuum phase, please refer to Table 27.37). The number of workers is determined based on the number of indexes on the relation that support parallel vacuum operation which is limited by number of workers specified with PARALLEL option if any which is further limited by max_parallel_maintenance_workers." instead of what is currently there? -- With Regards, Amit Kapila.
