Tom, Ah, that makes more sense. Thank you very much!
On Tue, Aug 30, 2016 at 9:15 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Luke Gordon <gord...@gmail.com> writes: > > However, according to a message on this mailing list, Postgres doesn't > have > > clustered indexes: > > "But Postgres doesn't _have_ clustered indexes, so that article doesn't > > apply at all. The other authors appear to have missed this important > point." > > https://www.postgresql.org/message-id/56798352.7060902%40uchicago.edu > > > But, doing a quick check, it appears Postgres does indeed have a > mechanism > > for a clustered index: > > https://www.postgresql.org/docs/9.5/static/sql-cluster.html > > CLUSTER just does a one-time sort to put the table into index order. > There is no mechanism that would cause subsequent insertions of new keys > to respect that ordering, so it's pretty much irrelevant to the argument > about whether new UUID keys need to be generated in some ordered fashion. > > Do you actually *need* UUID keys, and if so why? A plain old bigint > column is smaller, cheaper to index, and the natural mechanism for > generating it (ie a sequence) will tend to preserve ordering for free. > > regards, tom lane >
