Обсуждение: [HACKERS] Turn off transitive joins
Hi all,
Is there some way by which I can tell postgresql to not to consider transitive joins while considering join pairs.
I.e. Let's say a query has two join predicates one between A & B relations and the other between B and C relations.
While constructing the DP to find the best join order, the Optimizer also consider join between A & C, which can be thought of as a transitive join.
Is their some way to turn this off or tell postgresql to not to consider these type of joins ?
Gourav Kumar <gourav1905@gmail.com> writes: > Is there some way by which I can tell postgresql to not to consider > transitive joins while considering join pairs. No ... and you have presented no reason whatever why we should consider adding such a capability. Maybe you should be trying to construct your join graph someplace earlier, before the optimizer processes the join quals. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
I don't think there is any need to add any such capability in postgresql, but I need it for my work.
I need the join qualifiers.
On 15-Oct-2017 1:37 AM, "Tom Lane" <tgl@sss.pgh.pa.us> wrote:
Gourav Kumar <gourav1905@gmail.com> writes:
> Is there some way by which I can tell postgresql to not to consider
> transitive joins while considering join pairs.
No ... and you have presented no reason whatever why we should consider
adding such a capability.
Maybe you should be trying to construct your join graph someplace
earlier, before the optimizer processes the join quals.
regards, tom lane