Oracle: Init parameters PARALLEL_MIN_SERVERS and PARALLEL_MAX_SERVERS
The value of parallel_min_servers specifies the number of processes that are pre-allocated for parallel execution at instance startup. They remain until the instance is shut down.
The value of parallel_max_servers specifies the maximum number of proceses that can be used for parallel execution.
As per MOS Note 1503339.1, the value of parallel_servers_target should be 50-75 of parallel_max_servers.
select
name,
to_number(value) value
from
v$parameter
where
name in (
'parallel_min_servers', 'parallel_max_servers', 'parallel_servers_target',
'cpu_count', 'cpu_min_count'
)
union all
select
stat_name,
value
from
v$osstat
where
stat_name in (
'NUM_CPUS', 'NUM_CPU_CORES', 'NUM_CPU_SOCKETS'
)
;
Compare configured values with actual number of processed used for parallel processing:
select count(*) from v$px_process union all
select count(*) from v$pq_slave union all
select to_number(value) from v$parameter where name = 'parallel_min_servers' union all
select to_number(value) from v$parameter where name = 'parallel_max_servers';
See also
select * from v$resource_limit where name = 'parallel_max_servers';