You are working on an online transaction processing (OLTP) system. The CUST table in the SH schema was populated by direct load and after that it has gone through a lot of updates and deletions. The statistics for the CUST and SALES tables were updated recently.View the Exhibit and examine the query plan.The query is performing a lot of I/O for a query that fetches only 168 rows. To investigate further, you queried the ALL_TABLES view to find out PCTUSED, PCTFREE, and the number of rows in the CUST table, as given below: SQL> SELECT table_name ,blocks, pct_used, pct_free, num_rows 2 FROM all_tables 3* WHERE table_name = ‘CUST’; TABLE_NAME BLOCKS PCT_USED PCT_FREE NUM_ROWS ———- ———- ———- ———- ———- CUST 13768 80 111060 What would you recommend to reduce the I/O?
A. reorganizing the table to use fewer blocks
B. rebuilding the index on the CUST_FIRST_NAME column
C. increasing the value for the PCTFREE attribute for the CUST table
D. increasing the value for the PGA_AGGREGATE_TARGET initialization parameter
Answer:A
You are working on an online transaction processing (OLTP) system. The CUST table in the SH schema was populated by direct load and after that it has gone through a lot of updates and deletions. The statistics for the CUST and SALES tables were updated recently.View the Exhibit and examine the query plan.The query is performing a lot of I/O for a query that fetches only 168 rows. To investigate further, you queried the ALL_TABLES view to find out PCTUSED, PCTFREE, and the number of rows in the CUST table, as given below: SQL> SELECT table_name ,blocks, pct_used, pct_free, num_rows 2 FROM all_tables 3* WHERE table_name = ‘CUST’; TABLE_NAME BLOCKS PCT_USED PCT_FREE NUM_ROWS ———- ———- ———- ———- ———- CUST 13768 80 111060 What would you recommend to reduce the I/O?
A. reorganizing the table to use fewer blocks B. rebuilding the index on the CUST_FIRST_NAME column C. increasing the value for the PCTFREE attribute for the CUST table D. increasing the value for the PGA_AGGREGATE_TARGET initialization parameter