Rumpi Gravenstein <rgravens@xxxxxxxxx> writes: > Is this a PostgreSQL bug? Maybe, but you haven't provided enough information to let anyone else reproduce the behavior. Personally I'm suspicious that because your lag() calls are over partition by p.logical_partition_key, p.txt order by indx but then you filter by where logical_partition_key='TEST_DATA' and usage_text='F(T61)(EXPORT)'; that the lag() functions are seeing some rows that don't show up in the final output. (This'd require that some output rows from "parse" share txt values but not usage_text values, but that certainly looks like it's possible.) So IMO you have not actually demonstrated that there is any bug. regards, tom lane