On 2020-01-24 13:29, Matthias Winkler spmm...@gmail.com [firebird-support] wrote: > Hello, > > With Firebird 2.1.7 this statement freezes my firebird server > completely. Firebird will > take 100% CPU. > >> select first(8) ID from TBL_TEST >> where ID not in (select first(2) ID from TBL_TEST order by ID desc) >> order by ID desc > > The used table has about 18`000 entries. > > If I remove ONE of the order statements the query runs fine and takes > around 3s. > > Can somebody explain what execution plan is made for this statement > and > why it might sent my server into 100% CPU? > > Note: The statement here is simplified from my real usecase. The > statement itself might > not look useful. But that is not the point.
Firebird 2.1 has been end-of-life for more than five years. Can you reproduce this with Firebird 3.0? Mark
