Re: [PERFORM] max partitions behind a view? - Mailing list pgsql-performance

From Tom Lane
Subject Re: [PERFORM] max partitions behind a view?
Date
Msg-id 9918.1505742908@sss.pgh.pa.us
Whole thread Raw
In response to [PERFORM] max partitions behind a view?  (Rick Otten <rottenwindfish@gmail.com>)
List pgsql-performance
Rick Otten <rottenwindfish@gmail.com> writes:
> The challenge is that because of an exponential rate of data growth, I
> might have to significantly increase the number of partitions I'm working
> with - to several hundred at a minimum and potentially more than 1000...

> This leads me to the question how many 'union all' statements can I have in
> one view?

I don't think there's a hard limit short of INT32_MAX or so, but I'd be
worried about whether there are any O(N^2) algorithms that would start
to be noticeable at the O(1000) level.

> Should I create a hierarchy of views to gradually roll the data
> up instead of putting them all in one top-level view?

That would likely make things worse not better; the planner would flatten
them anyway and would expend extra cycles doing so.  You could perhaps
stop the flattening with optimization fences (OFFSET 0) but I really doubt
you want the side-effects of that.
        regards, tom lane


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