Oracle Multi-CPU parallel query ____oracle

T_medflow table has 10 million data flowid is primary key has primary key index

Total number of statistics

Select COUNT (flowid) from T_medflow t

Spents: 1.5 seconds

Select COUNT (*) from T_medflow t

Spents: 1.46 seconds

Multiple test efficiency is almost

Add a conditional query

Select COUNT (flowid) from T_medflow t where pname like '% '

Spents: 25S [The total number of statistics for a query is 25 seconds and the basic user experience is very poor]

Statistical analysis of the following table to prevent the wrong execution plan

ANALYZE TABLE t_medflow COMPUTE STATISTICS;

are checking

Select COUNT (flowid) from T_medflow t where pname like '% '

Spents: 22 seconds

Using multiple CPUs for parallel processing

Select/*+ PARALLEL (t_medflow,14) */COUNT (*) from T_medflow
Where pname like '% of% '

Spents: 1.7 Seconds [My database environment is 4CPU]

Solve the problem of count (*) slow

The number of CPU settings based on the actual number of CPUs will not be more than 4 times CPU but inefficient

Using indexes for parallel efficiency is low don't know what the problem is

Select/*+ Parallel_index (T_medflow, Pk_flowid,)/count (*) from T_medflow
Where pname like '% of% '