We saw error ORA-00439 when we tried to create an index online.
SQL> create index erp.bill_hist_idx2 on erp.bill_hist (SQ_NO) online;
create index erp.bill_hist_idx2 on erp.bill_hist (SQ_NO) online
ERROR line 1:
ORA-00439: feature not enabled: Online Index Build
ORA-00439 means that the feature you were using is not enabled or supported in this edition which might be a standard edition (SE) or an express edition (XE).
To solve ORA-00439, you should use feature in the enterprise edition (EE). To migrate from the standard edition to the enterprise edition, you may perform an in-place upgrade or install a new Oracle home for the enterprise edition.