Hi, On 2018-03-29 17:27:47 -0400, Tom Lane wrote: > Andres Freund <and...@anarazel.de> writes: > > There's plenty databases with pg_attribute being many gigabytes large, > > and this is going to make that even worse. > > Only if you imagine that a sizable fraction of the columns have fast > default values, which seems somewhat unlikely.
Why is that unlikely? In the field it's definitely not uncommon to define default values for just about every column. And in a lot of cases that'll mean we'll end up with pg_attribute containing default values for most columns but the ones defined at table creation. A lot of frameworks make it a habit to add columns near exclusively in incremental steps. You'd only get rid of them if you force an operation that does a full table rewrite, which often enough is impractical. Greetings, Andres Freund
