Christopher Browne wrote:
In the last exciting episode, [EMAIL PROTECTED] (David Link) wrote:
Why does adding SUM and GROUP BY destroy performance?
When you use SUM (or other aggregates), there are no short cuts to
walking through each and every tuple specified by the WHERE clause.
Er... not in
In the last exciting episode, [EMAIL PROTECTED] (David Link) wrote:
Why does adding SUM and GROUP BY destroy performance?
When you use SUM (or other aggregates), there are no short cuts to
walking through each and every tuple specified by the WHERE clause.
On some systems there are statistics
Thanks Ron, Thanks Christopher for your excellent feedback.
I guess it's back to the drawing board. This is a very late hour
business requirement change. And we need quick real-time results.
Two things are being considered:
1. loading the non aggregate query entirely into memory (using
Hi,
Why does adding SUM and GROUP BY destroy performance?
details follow.
Thanks, David Link
s1.sql:
SELECT
t.tid, t.title,
COALESCE(s0c100r100.units, 0) as w0c100r100units,
(COALESCE(r1c2r100.units, 0) + COALESCE(y0c2r100.units, 0))
as r0c2r100units
