This one quite nicely explains it: https://stackoverflow.com/questions/14897816/how-can-i-prevent-postgres-from-inlining-a-subquery
On Wed, Dec 8, 2021 at 3:14 AM David G. Johnston <david.g.johns...@gmail.com> wrote: > On Tue, Dec 7, 2021 at 6:40 PM Дмитрий Иванов <firstdis...@gmail.com> > wrote: > >> I beg your pardon. >> The problem is more or less clear to me, but the solution is not. What >> does the "hack is to add an "offset 0" to the query" suggest? Thank you. >> >> > A subquery with a LIMIT clause cannot have where clause expressions in > upper parts of the query tree pushed down it without changing the overall > query result - something the planner is not allowed to do. For the hack, > since adding an actual LIMIT clause doesn't make sense you omit it, but > still add the related OFFSET clause so the planner still treats the > subquery as a LIMIT subquery. And since you don't want to skip any rows > you specify 0 for the offset. > > David J. > >
