Re: Proposal: Global Index

On Mon, Jan 11, 2021 at 12:05:43PM -0800, Peter Geoghegan wrote:
> On Mon, Jan 11, 2021 at 11:25 AM Bruce Momjian <bruce@momjian.us> wrote:
> > Once you layer on all the places a global index will be worse than just
> > creating a single large table, or a partitioned table with an index per
> > child, there might not be much usefulness left.  A POC patch might tell
> > us that, and might allow us to mark it as "not wanted".
> 
> I'm confused. Of course it's true to some degree that having a global
> index "defeats the purpose" of having a partitioned table. But only to
> a degree. And for some users it will make the difference between using
> partitioning and not using partitioning -- they simply won't be able
> to tolerate not having it available (e.g. because of a requirement for
> a unique constraint that does not cover the partitioning key).

Yes, that is a good point.  For those cases, I think we need to look at
the code complexity/overhead of supporting that feature.  There are
going to be a few cases it is a win, but will the code complexity be
worth it?

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

  The usefulness of a cup is in its emptiness, Bruce Lee