Hi Magnus,
Thanks for the heads up.
For the data posted in this email, the listed result is the full result
set for that query.
I have checked the data in view2 and view1 with various conditions.
Both view has many difference in column wspan::float8.
The condition in the shown query is intended to show just a small set of
them.
But you are right, I should be more cautious. Thanks for the headsup.
Regards,
Ben
On 9/16/20 3:35 PM, Magnus Hagander wrote:
On Wed, Sep 16, 2020 at 9:26 AM Ben <benten...@outlook.com
<mailto:benten...@outlook.com>> wrote:
Dear list,
Recently I am getting feedback, data in my analytic report is not
repeatable. From time to time they get different data for the same
time
span.
(but IIRC previously it was OK). Therefore I started debuging the
View
chain for that report, during which I bumped into this
issue/phenomenon.
In a over -simplified version:
CREATE VIEW2 AS SELECT * FROM VIEW1;
SELECT col1 FROM VIEW2 WHERE cond1=True;
SELECT col1 FROM VIEW1 WHERE cond1=True;
Now col1 from both views looks different. I don't know where to
start to
solve this problem.
The actual situation is a bit more than that, the following is the
actual query:
-- trying to audit utlog weighed stat
with t as (
select '2020-07-01 00:00:00'::timestamp t0, '2020--07-02
0:0:0'::timestamp t1
)
--select * from t;
select *
-- from utlog.cache_stats_per_shift_per_reason_weighed_stats
-- from utlog.stats_per_shift_filtered_per_reason
from utlog.stats_per_shift_filtered (let's call
it #View2 for short)
-- from utlog.stats_per_shift_filtered_b0206 (let's call it
#View1 for short)
-- from utlog.stats_per_shift
cross join t
where wline = 'F02' and wts >= t.t0 and wts < t.t1 and wsft ='D'
limit 100
;
Not sure if it might be something lost in your simplification here,
but you have a LIMIT with no ORDER BY there. That basically means
"give me 100 random rows" (but not with a very good random level). It
does not return rows in a consistent/predictable order. So as long as
that query is part of what you're doing, you should not be surprised
if you get the rows in an inconsistent/unpredictable order, with
whatever follow-on effects that might have. (And it can lead to weird
follow-on effects like the ones you're talking about when used in
larger query structures)
--
Magnus Hagander
Me: https://www.hagander.net/ <http://www.hagander.net/>
Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>
