1Z1-054 Free Dumps Study Materials
Question 5: View Exhibit1 and examine the indexes on the CUSTOMERS table.
The statistics for the CUSTOMERS table have been updated recently by using the following command:
SQL> EXEC DBMS_STATS.GATHER_TABLE_STATS('SH','CUSTOMERS',method_opt=>'FOR ALL
INDEXED COLUMNS SIZE AUTO');
View Exhibit2 to examine a query plan. Even though the index is present on the COUNTRY_ID and
CUST_GENDER columns, the query uses a full table scan. What could be the reason?
A. because the histogram statistics for the COUNTRY_ID column are not updated
B. because the DB_FILE_MULTIBLOCK_READ_COUNT initialization parameter is set to a high value
C. because the optimizer calculates the cost of accessing blocks by using a full table scan to be less as
compared to index scans, even though indexes are available
D. because indexes on CUST_GENDER and COUNTRY_ID columns are of different types, the index on
the CUST_GENDER column is bitmap index, and on COUNTRY_ID columns is btree index.
ANSWER: C