On Tue, Oct 3, 2017 at 8:16 AM, Amit Khandekar <amitdkhan...@gmail.com> wrote:
> While writing this down, I observed that after multi-level partition
> tree expansion was introduced, the child table expressions are not
> converted directly from the root. Instead, they are converted from
> their immediate parent. So there is a chain of conversions : to leaf
> from its parent, to that parent from its parent, and so on from the
> root. Effectively, during the first conversion, there are that many
> ConvertRowtypeExpr nodes one above the other already present in the
> UPDATE result rel expressions. But my patch handles the optimization
> only for the leaf partition conversions.
> If already has CRE : CRE(rr) -> wr(r)
> Parent-to-child conversion ::: CRE(p) -> wr(r)  ===>   CRE(rr) ->
> CRE(r) -> wr(c1)
> W patch : CRE(rr) -> CRE(r) -> wr(c1) ===> CRE(rr) -> CRE(r) -> wr(c2)

Maybe adjust_appendrel_attrs() should have a similar provision for
avoiding extra ConvertRowTypeExpr nodes?

Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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