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)