> On Fri, Oct 8, 2021, at 6:33 AM, nikolai.berkoff wrote: > > Running --analyze-in-stages on a database with statistics causes the > > statistics to become significantly worse before they are improved. > > This could be made clearer in the documentation. > > I think the paragraph you modified *already* stated that usefulness of > --analyze-in-stages (newly populated from a restored dump or by pg_upgrade). I > don't think your change is an improvement for --analyze-in-stages description. > If you read the previous paragraph, it explains _how_ (3 stages of ANALYZE with > different settings) and _why_ (produce usable statistics faster).
Yeah, but it doesn't say that the initial stats target (1) is the worst value you could possibly have. [...] Given that the first stage uses statistic target=1, running this option in a database with any stats at all is probably a bad idea.
Add the word "only"?
This option is only useful to analyze a database...
Beyond that maybe adjust the procedure description to include a comment that we don't actually skip tables that already have a higher statistics target than the current pass would apply. (can we do this?)
"Run several (currently three) stages of analyze with different configuration settings, to produce usable statistics faster. The first of these stages will remove any existing statistics even if they use a larger statistic target configuration."