On Thu, Feb 22, 2018 at 12:35 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <rhaas@postgresql.org> writes:
>> Charge cpu_tuple_cost * 0.5 for Append and MergeAppend nodes.
>
> This seems to have produced some plan instability in the buildfarm.
I was worried about that. Looking at it now. I wish we had some way
to figure out whether a given plan was likely to be unstable on the
buildfarm other than committing it and seeing what happens. It's
surprisingly difficult to write non-trivial tests that produce
consistent EXPLAIN output, and annoyingly time-consuming to try to
figure out why they don't.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company