[Oracle] 初始化参数1

RECOVERY_PARALLELISM

RECOVERY_PARALLELISM specifies the number of processes to participate in instance or crash recovery. A value of 0 or 1 indicates that recovery is to be performed serially by one process.

PARALLEL_MAX_SERVERS

PARALLEL_MAX_SERVERS specifies the maximum number of parallel execution processes and parallel recovery processes for an instance. As demand increases, Oracle increases the number of processes from the number created at instance startup up to this value.
If you set this parameter too low, some queries may not have a parallel execution process available to them during query processing. If you set it too high, memory resource shortages may occur during peak periods, which can degrade performance.

PARALLEL_MIN_SERVERS

PARALLEL_MIN_SERVERS specifies the minimum number of parallel execution processes for the instance. This value is the number of parallel execution processes Oracle creates when the instance is started.

PARALLEL_MIN_PERCENT

PARALLEL_MIN_PERCENT operates in conjunction with PARALLEL_MAX_SERVERS and PARALLEL_MIN_SERVERS. It lets you specify the minimum percentage of parallel execution processes (of the value of PARALLEL_MAX_SERVERS) required for parallel execution. Setting this parameter ensures that parallel operations will not execute
sequentially unless adequate resources are available. The default value of 0 means that no minimum percentage of processes has been set.