Histograms - 10.2.0.4

 

We have a table with highly skewed value distribution in one of the coulmns (see below)


SQL> select invoice_prepared,count(*) from invoice_header group by invoice_prepared;

I   COUNT(*)
- ----------
Y     737731
N         10

Its a 10.2.0.4 Database

we created histogram on this column as below

execute DBMS_STATS.GATHER_TABLE_STATS(OWNNAME => 'APPSDBA', TABNAME => 'INVOICE_HEADER',METHOD_OPT => 'FOR COLUMNS SIZE 2 INVOICE_PREPARED',CASCADE => TRUE);

We have 3 questions:

# 1) How can we verify that we now have histograms in place for this column that the optimizer will consider while selecting execution plan

# 2) How would we delete the histogram on this column if we want to