Exam 1z0-054 topic 1 question 20 discussion

Actual exam question from Oracle's 1z0-054

Question #: 20
Topic #: 1

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

Show Suggested Answer

Suggested Answer: C 🗳️

by [deleted] at April 4, 2025, 8:35 a.m.

Comments

Submit Cancel

Currently there are no comments in this discussion, be the first to comment!