Re: Performance problem on 2 PG versions on same query

Thank you very much for the insights (and how to read correctly a explain
:)).
There is a difference in data between the 2 databases, crons where running
on one and not the other.

But your insights enabled us to dive deeper, thanks !

2014-11-05 18:30 GMT+01:00 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:

> "Tomas Vondra" <tv(at)fuzzy(dot)cz> writes:
> > Dne 5 Listopad 2014, 18:10, Tom Lane napsal(a):
> >> For some reason there's over 1000 times more rows in andalertsmatch in
> >> the 9.1.14 installation. I'm betting on a foulup somewhere in the data
> >> dump/restore process.
>
> > I'd bet that's mostly due to rescans in the merge join ...
>
> Doh, I should have thought of that :-(. But still, the difference in
> the number of final output rows is pretty compelling evidence that
> it's not really the same data.
>
> regards, tom lane
>