No xmin column in Citus columnar storage. Is there a way around?

[tuttle]

It appears the tap requires xmin column as the replication bookmark.

The column certainly exists for standard PostgreSQL access method, however Citus columnar storage does not provide any of the system columns (https://www.postgresql.org/docs/14/ddl-system-columns.html).

Is there any way around it so this tap can be used to fully replicate the columnar table, please?

[tuttle]

Looking at the code, I was considering two options to solve this:

1. add disable_xmin_resuming bool option to skip requesting the xmin column from the database in sync_table,
   or
2. extend the SELECT ... FROM pg_attribute, pg_class... in produce_table_info() to treat the columnar table as view, as these table are not updatable anyway.

I was also comparing the sync_table() and sync_view() functions. Here's the diff: https://gist.github.com/tuttle/e8595eebbf492dbe60ee9ca18dc92af6
While it appears there is no xmin used in sync_view, which is what I'd needed, there are a few more differences. Some of them could be the developer forgot to update sync_view, when sync_table was extended. Not sure.

Would any of the two solutions mentioned be accepted as PR, please? Any other solutions occurs here?

[halilduygulu]

Xmin is a problem even it exists in postgres, order by xmin is very very slow for 100+ million row tables.
I had to use pipelinewise fastsync for this reason, which is running copy to stdout from tables and at least 3x faster to do a full copy of a table.