Nathan Boley <npboley@xxxxxxxxx> writes: >> The accesses to an index are far more likely to be clustered than the >> accesses to the underlying table, because the index is organized in a >> way that's application-meaningful and the table not so much. > So, to clarify, are you saying that if query were actually requesting > rows uniformly random, then there would be no reason to suspect that > index accesses would have hotspots? It seems like the index structure > ( ie, the top node in b-trees ) could also get in the way. The upper nodes would tend to stay in cache, yes, but we already assume that in the index access cost model, in a kind of indirect way: the model only considers leaf-page accesses in the first place ;-) regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
