I have an idea for what I think may be a very simple optimization for postgres
to make. I would like to try my hand at implementing it, but the last time I
tried I apparently started off in the wrong direction.
In the following query, the sort step is completely unnecessary. The order is
Greg Stark kirjutas N, 04.12.2003 kell 19:55:
I have an idea for what I think may be a very simple optimization for postgres
to make. I would like to try my hand at implementing it, but the last time I
tried I apparently started off in the wrong direction.
In the following query, the sort
Hannu Krosing kirjutas N, 04.12.2003 kell 23:01:
Where should I be looking in the code?
Try to find where the modified query is tested for. It's probably be
inside the optimizer, as index scan + no sort is not always faster than
seq scan + sort, as shown by the same query after vacuum
Greg Stark [EMAIL PROTECTED] writes:
At what point in the process would it make sense to check for this?
You'd need to mess with the code that generates pathkeys describing
the sort ordering of index scans --- read about pathkeys in
src/backend/optimizer/README. As Hannu notes nearby, the
