On 2018-06-21 13:44:19 -0400, Tom Lane wrote: > Andrew Dunstan <andrew.duns...@2ndquadrant.com> writes: > > On 06/21/2018 01:18 PM, Tom Lane wrote: > >> I might be OK with a patch that converts *all* of pg_dump's cross-version > >> difference handling code to depend on PQfnumber silently returning -1 > >> rather than failing, but I don't want to see it done like that in just > >> one or two places. > > > I don't mind changing it. But please note that I wouldn't have done it > > that way unless there were a precedent. I fully expected to add dummy > > values to all the previous queries, but when I couldn't find attidentity > > in them to put them next to I followed that example. > > Actually, now that I think about it, there is a concrete reason for the > historical pattern: it provides a cross-check that you did not fat-finger > the query, ie misspell the column alias vs the PQfnumber parameter. This > gets more valuable the more per-version variants of the query there are. > With the way the attidentity code does it, it would just silently act as > though the column has its default value, which you might or might not > notice in cursory testing. Getting visible bleats about column number -1 > is much more likely to get your attention.
To me that benefit is far smaller than the increased likelihood of screwing something up because you'd to touch pg_dump support for postgres versions one likely doesn't readily have available for testing. Greetings, Andres Freund
