Gregory Stark <stark@enterprisedb.com> writes:
> In particular I'm thinking of people clustering on a covering index (which
> isn't as uncommon as it sounds, if you have a covering index you probably do
> want to cluster it -- consider many-to-many join tables). We should be able to
> do an index-only scan which might be even faster than sorting.
[ scratches head... ] You need *all* the data from the heap. Or by
"covering index" do you mean an index that contains the entire table
contents? Doesn't really sound like a case we need to focus on; or
at least this version of clustering isn't what it needs, it wants an
implementation where the table and the index are the same thing.
regards, tom lane