> On Jul 24, 2020, at 06:48, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > > There's certainly not a lot besides tradition to justify the exact > numbers used in this case. Since we already special-case parent tables for partition sets, would a storage parameter that lets you either tell the planner "no, really, zero is reasonable here" or sets a minimum number of rows to plan for be reasonable? I happened to get bit by this tracking down an issue where several tables in a large query had zero rows, and the planner's assumption of a few pages worth caused some sub-optimal plans. The performance hit wasn't huge, but they were being joined to some *very* large tables, and the differences added up. -- -- Christophe Pettus xof@xxxxxxxxxxxx
