DBMS_STATS.IMPORT_DATABASE_STATS taking long time

Hello experts,

                       I am using transportable tablespace feature to migrate a huge data warehouse database (~20 TB) from SOLARIS to LINUX x86-64 platform.During metadata import phase I have excluded stats and importing now using stats table.

I was in impression that it will save some time with this but I see it has been running since last 5 hours and still not yet complete.When I did it first time metdata import took 6 hours and on that stats import phase took almost 5 hrs.

As a side note during import follwing errors appeared
SQL> EXEC DBMS_STATS.IMPORT_DATABASE_STATS(stattab => 'OPT_STATS');