On Wed, Oct 27, 2021 at 2:32 AM Robert Haas <robertmh...@gmail.com> wrote: > > On Tue, Oct 5, 2021 at 6:50 AM Simon Riggs <simon.ri...@enterprisedb.com> > wrote: > > With unique data, starting at 1 and monotonically ascending, hash > > indexes will grow very nicely from 0 to 10E7 rows without causing >1 > > overflow block to be allocated for any bucket. This keeps the search > > time for such data to just 2 blocks (bucket plus, if present, 1 > > overflow block). The small number of overflow blocks is because of the > > regular and smooth way that splits occur, which works very nicely > > without significant extra latency. > > It is my impression that with non-unique data things degrade rather > badly. >
But we will hold the bucket lock only for unique-index in which case there shouldn't be non-unique data in the index. The non-unique case should work as it works today. I guess this is the reason Simon took an example of unique data. -- With Regards, Amit Kapila.
