| From: | Joe Conway <mail(at)joeconway(dot)com> |
|---|---|
| To: | David Walker <pgsql(at)grax(dot)com> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: About connectby() |
| Date: | 2002-09-07 17:34:07 |
| Message-ID: | 3D7A388F.3020800@joeconway.com |
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| Thread: | |
| Lists: | pgsql-hackers pgsql-patches |
David Walker wrote:
> I prefer the max depth method. Every tree I am aware of has a maximum usable
> depth.
>
> This should never be a problem in trees where keyid is unique.
>
I just sent in a patch using the ancestor check method. It turned out
that the performance hit was pretty small on a moderate sized tree.
My test case was a 220000 record bill-of-material table. The tree built
was 9 levels deep with about 3800 nodes. The performance hit was only
about 1%.
Are there cases where infinite recursion to some max depth *should* be
allowed? I couldn't think of any. If a max depth was imposed, what
should it be?
Joe
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