Tuesday, November 25, 2008

PARALLEL_MAX_SERVERS

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Property
Description
Parameter type
Integer
Default value
Derived from the values of CPU_COUNT, PARALLEL_THREADS_PER_CPU, and PGA_AGGREGATE_TARGET
Modifiable
ALTER SYSTEM
Range of values
0 to 3600
Real Application Clusters
Multiple instances can have different values.
Note:
1. This parameter applies to parallel execution in exclusive mode as well as in a Real Application Clusters environment.
PARALLEL_MAX_SERVERS specifies the maximum number of parallel execution processes and parallel recovery processes for an instance. As demand increases, Oracle Database increases the number of processes from the number created at instance startup up to this value.
If you set this parameter too low, then some queries may not have a parallel execution process available to them during query processing. If you set it too high, then memory resource shortages may occur during peak periods, which can degrade performance.
2. Query for the current value of the parameter
select name, value, isdefault, isses_modifiable, issys_modifiable,
isinstance_modifiable, isdeprecated, description
from v$parameter where upper(name) = ‘PARALLEL_MAX_SERVERS’;
NAME
VALUE
IS
DEFAULT
ISSES_
MODIFIABLE
ISSYS_
MODIFIABLE
ISINSTANCE_
MODIFIABLE
IS
DEPRECATED
DESCRIPTION
parallel_max_servers
80
TRUE
FALSE
IMMEDIATE
TRUE
FALSE
maximum parallel query
servers per instance

Oracle initializatoin parameters