Execute the SQL statement with "EXPLAIN ANALYZE" to check the following:

• If a VCI was used
  "Custom Scan (VCI...)" is displayed in the plan if a VCI was used.

• Number of parallel processes
  The number of parallel processes when the SQL statement is executed is displayed in "Allocated Workers". Check that it is running the designed number of parallel processes.

• Response
  Check if the execution time displayed in "Execution time" is as estimated.

The following shows an example of the output result of EXPLAIN ANALYZE:

EXPLAIN ANALYZE SELECT COUNT(*) FROM test WHERE x > 10000;
                                                    QUERY PLAN                                                     
-------------------------------------------------------------------------------------------------------------------
Custom Scan (VCI Aggregate)  (cost=19403.15..19403.16 rows=1 width=0) (actual time=58.505..58.506 rows=1 loops=1)
	   Allocated Workers: 4
   ->  Custom Scan (VCI Scan) using test_x_idx on test (cost=0.00..16925.00 rows=991261 width=0) (never executed)
         Filter: (x > 10000)
Planning time: 0.151 ms
Execution time: 86.910 ms
(6 rows)