Oracle 参数 AWR_PDB_MAX_PARALLEL_SLAVES 官方解释，作用，如何配置最优化建议
本站中文解释
参数
AWR_PDB_MAX_PARALLEL_SLAVES参数用于指定系统可以使用的从库的最大并行度。通常用于并行计划报告中，特别是大型报告，其中需要做大量运算，以提高报告处理速度。
该参数可以在Oracle控制文件中进行设置，可以使用以下方法：
ALTER SYSTEM SET AWR_PDB_MAX_PARALLEL_SLAVES =
如果要正确设置该参数，原则应该如下：
1.该参数的值通常取决于数据库中的并行操作系统，因此它的值应该不大于每个从库的最大运行度数。
2.该参数也可以根据预期的AWR报表大小动态调整，以便获得最佳性能。
官方英文解释
AWR_PDB_MAX_PARALLEL_SLAVES enables a DBA to allocate the correct amount of resources to enable quick and timely Automatic Workload Repository (AWR) flushes for multitenant container databases (CDBs).
| Property | Description |
|---|---|
|
Parameter type |
Integer |
|
Default value |
10 |
|
Modifiable |
|
|
Modifiable in a PDB |
No |
|
Range of values |
1 – 30 |
|
Basic |
No |
|
Oracle RAC |
Different instances can use different values. |
Use AWR_PDB_MAX_PARALLEL_SLAVES to control the amount of resources dedicated to AWR snapshot flushing in pluggable databases (PDBs). With this parameter, a DBA can modify the maximum number of MMON slave processes (Mnnn background processes) that can concurrently be used to handle AWR flush operations for the entire CDB.
For CDBs with a large number of PDBs enabled to create automatic AWR snapshots, a DBA can increase this parameter to enable timely AWR flushing. For CDBs with a small number of PDBs enabled, the value of this parameter can be decreased to reduce the concurrency and the chance of performance spikes.
Note that this parameter is set in the root of a CDB and determines the maximum degree of parallelism used to create AWR automatic snapshots for PDBs.
See Also:
-
“AWR_PDB_AUTOFLUSH_ENABLED” for information about enabling the automatic creation of AWR PDB snapshots
-
Oracle Database
Performance Tuning Guide for an introduction to AWR -
“Background Processes” for more information about the MMON and Mnnn background processes
