By explicitly making a column an IDENTITY column it is going to make a sequence behind the scenes even if one with a similar name exists. I tried and it created part_tab_part_id_seq1. Is there no way to have it use the original part_tab_part_id_seq? How do I get the data and the sequence in sync?
If I run these two statements I get an error ERROR: relation "part_tab_part_id_seq" already exists
I tried different combinations of this ALTER TABLE statement and none seem to work. What is the proper way to reattach the identity and the sequence bearing in mind that I will load the new table with the data from the old table?
So remove the generated by default from the old non-partitioned table (manually drop the sequence if needed too'. Or just choose a different sequence name for the new one.
"reattach the identity" isn't a thing - the system is telling you it is creating a new one and you will need to synchronize it to your data.