On Sat, 4 Jun 2016 Andrew Beverley <andy@andybev.com> wrote:
> I'm performing a query with many joins, with a WHERE condition on the
> "root" table. As far as I am aware, each join is indexed, as is the
> WHERE clause. To my simple mind, this is just a case of taking a set
> of conditional indexed values, and then "adding on" the relevant
> indexed data.
Apologies, I think I've found the problem. All the joined table are
meant to have only a single value for the "root" table, but there were
actually several for some, which was exponentially adding many rows for
all the joins. I've not tried it yet, but I suspect that once I fix
that the performance will be as expected.