We are unable to get a user import with HR Import using our external DB 

We get an error that references a table that does not exist. "mdl_totara_sync_user"

Server time: 2 May 2017 at 10:47:41, Element: user, Action: unknown, Error:
Error writing to database - ERROR:  null value in column "idnumber" violates not-null constraint
DETAIL:  Failing row contains (1, null, 0, , null, null, null, null, []).
INSERT INTO mdl_totara_sync_user
(idnumber,timemodified,username,firstname,lastna...

can't find it here
https://autodocs.totaralms.com/schemaspy/totara-9.0/

We do have a value in idnumber column for all users, and we have usernames not an empty column as it assumes.