Re: Recursive query syntax ambiguity - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Recursive query syntax ambiguity
Date
Msg-id 446.1170692638@sss.pgh.pa.us
Whole thread Raw
In response to Re: Recursive query syntax ambiguity  (Martijn van Oosterhout <kleptog@svana.org>)
List pgsql-hackers
Martijn van Oosterhout <kleptog@svana.org> writes:
> However, I don't know it matters. You only need to cost the plan if
> there are alternate paths and given the plan structure is strongly
> constrained, I'm not sure how much it matters.

It does, since the whole thing could be a subquery, in which case there
could be options available at the outer level.  I doubt we'll be able to
be really smart, but that doesn't mean we can just punt.

> In the case of read-committed mode, will two seq-scans always
> return the same result?

They definitely should, since we'll be using the same snapshot
throughout the query.
        regards, tom lane


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