PARALLEL_THREADS_PER_CPU
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Property
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Description
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Parameter type
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Integer
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Default value
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Operating system-dependent, usually 2
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Modifiable
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ALTER SYSTEM
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Range of values
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Any nonzero number
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Note:
This parameter applies to parallel execution in exclusive mode as well as in a Real Application Clusters environment.
PARALLEL_THREADS_PER_CPU specifies the default degree of parallelism for the instance and determines the parallel adaptive and load balancing algorithms. The parameter describes the number of parallel execution processes or threads that a CPU can handle during parallel execution.
PARALLEL_THREADS_PER_CPU指定實例默認的并行度，確定合適的并行和負載均衡算法。這個參數(shù)描述并行執(zhí)行進程數(shù)，或者在并行執(zhí)行期間CPU能處理的線程數(shù)。
The default is platform-dependent and is adequate in most cases. You should decrease the value of this parameter if the machine appears to be overloaded when a representative parallel query is executed. You should increase the value if the system is I/O bound.
默認值依賴于平臺，在大多數(shù)情況下都是合適的。當執(zhí)行一個典型的并行查詢時，服務(wù)器出現(xiàn)過載的情況，應(yīng)該減少這個參數(shù)的值。如果系統(tǒng)在I/O的邊界應(yīng)該增加這個值。
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