Fujii Masao <masao.fu...@gmail.com> writes: > On Tue, Jul 7, 2015 at 12:49 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> One idea I had was to allow the COPY optimization only if the heap file is >> physically zero-length at the time the COPY starts.
> This seems not helpful for the case where TRUNCATE is executed > before COPY. No? Huh? The heap file would be zero length in that case. > So, if COPY is executed multiple times at the same transaction, > only first COPY can be optimized? This is true, and I don't think we should care, especially not if we're going to take risks of incorrect behavior in order to optimize that third-order case. The fact that we're dealing with this bug at all should remind us that this stuff is harder than it looks. I want a simple, reliable, back-patchable fix, and I do not believe that what you are suggesting would be any of those. 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