dbms_tabcomp_temp_uncmp and cmp tables in user's schema's 11.2.0.1

 Automated job 'Segment Advisor' creating and dropping dbms_tabcomp_temp_uncmp and cmp tables in user's schema's 11.2.0.1. Apparently it is doing the following,
Step 1 : create a temp table dbms_tabcomp_temp_uncmp  as select  *From from real_table1;
Step 2:  create a temp table dbms_tabcomp_temp_cmp
            organization heap
            compress for query high
            as select  * from dbms_tabcomp_temp_uncmp  ;

Step 3:  drop table dbms_ tabcomp_temp_uncmp;
Step 4:  drop table dbms_tabcomp_temp_cmp ;

Is this something expected ?
If so, does it do this for all the tables in the database ? IS there any worry about table spaces being filled up ?