Alvaro Herrera <alvhe...@2ndquadrant.com> writes: > Tom Lane wrote: >> [ pokes around... ] The code I was thinking of is convert_tuples_by_name >> in access/common/tupconvert.c. There's a bit of an API mismatch in that >> it wants to wrap the mapping array in a TupleConversionMap struct; but >> maybe we could refactor tupconvert.c to offer a way to get just the map >> array.
> Ah, nice gadget. I think the attached patch should do. Looks reasonable to me. >>> I also modified the algorithm to use the relcache instead of walking the >>> child's attribute list for each parent attribute (that was silly). >> Hmm. That might be better in a big-O sense but I doubt it's faster for >> reasonable numbers of columns. > Hm, I was thinking in unreasonable numbers of columns, keeping in mind > that they can appear in arbitrary order in child tables. Then again, > that probably seldom occurs in real databases. I suppose this could > become an issue with table partitioning becoming more common, but I'm > okay with deferring the optimization work. It occurred to me that it'd be really easy to improve convert_tuples_by_name so that, rather than having the inner loop start from j = 0 every time, it starts from the attribute after the last match (and loops around if needed, so that it still examines every child attribute). I think this would keep it at more-or-less linear time for all but very contrived child tables. Since your patch is touching that code I won't do anything about it right now, but maybe later. regards, tom lane -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers