Oracle Parallel initialization parameters

Parallel Oracle database operations, especially in the RAC environment, can improve the database performance to a certain extent. Therefore, it is necessary to understand the relevant initialization parameters.

Parallel Oracle database operations, especially in the RAC environment, can improve the database performance to a certain extent. Therefore, it is necessary to understand the relevant initialization parameters.

Parallel Oracle database operations, especially in the RAC environment, can improve the database performance to a certain extent. Therefore, it is necessary to understand the relevant initialization parameters, this article will discuss some parallel parameters of Oracle databases based on actual cases.

Parallel parameters related to Oracle databases:

SQL> show parameter parallel

NAME TYPE VALUE

------------------------------------------------------------------------------

Fast_start_parallel_rollback string LOW

Parallel_adaptive_multi_user boolean TRUE

Parallel_automatic_tuning boolean FALSE

Parallel_degree_limit string CPU

Parallel_degree_policy string MANUAL

Parallel_execution_message_size integer 16384

Parallel_force_local boolean FALSE

Parallel_instance_group string

Parallel_io_cap_enabled boolean FALSE

Parallel_max_servers integer 135

Parallel_min_percent integer 0

NAME TYPE VALUE

------------------------------------------------------------------------------

Parallel_min_servers integer 0

Parallel_min_time_threshold string AUTO

Parallel_server boolean FALSE

Parallel_server_instances integer 1

Parallel_servers_target integer 64

Parallel_threads_per_cpu integer 2

Recovery_parallelism integer 0

The following is the setting of Oracle Parallel parameters in the actual Oracle RAC environment. We will give priority to these parameters:

*. Parallel_adaptive_multi_user = FALSE

*. Parallel_execution_message_size = 16384

*. Parallel_max_servers = 240

*. Parallel_min_servers = 0

*. Parallel_threads_per_cpu = 1

PARALLEL_ADAPTIVE_MULTI_USER

PropertyDescription

Parameter typeBoolean

Default valuetrue

ModifiableALTER SYSTEM

Range of valuestrue | false

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PARALLEL_ADAPTIVE_MULTI_USER, when set to true, enables an adaptive algorithm designed to improve performance in multiuser environments that use parallel execution. the algorithm automatically has CES the requested degree of parallelism based on the system load at query startup time. the specified tive degree of parallelism is based on the default degree of parallelism, or the degree from the table or hints, pided by a limit ction factor. ITPUB personal space T (k (gsnA2i
When the PARALLEL_ADAPTIVE_MULTI_USER parameter is set to TRUE, the appropriate algorithm is enabled to improve performance by using parallel execution in a multi-user environment. This algorithm automatically reduces the request concurrency based on the system load when the query starts. The valid degree of parallelism is based on the default degree of parallelism, or the degree of parallelism from the table or HINT, which is split by reducing the coefficient.

The algorithm assumes that the system has been tuned for optimal performance in a single-user environment.
9 ^, {G5s4fCDH1W8g3v0 algorithm assumes that the system is adjusted according to the optimal performance in a single-user environment.

Tables and hints use the default degree of parallelism. ITPUB personal space G8 ["q ^ 8VxV2B % Sd
Tables and hints use the default degree of parallelism.

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PARALLEL_MAX_SERVERS

PropertyDescription

Parameter typeInteger

Default valuePARALLEL_THREADS_PER_CPU * CPU_COUNT * concurrent_parallel_users * 5

ModifiableALTER SYSTEM

Range of values0 to 3600

Oracle RACMultiple instances can have different values.

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Note:

This parameter applies to parallel execution in exclusive mode as well as in a Real Application Clusters environment.