关于并行默认内存分配是在shared_pool还是large_pool

qq7343696

       今天看书发现paralel_automatic_tuning为true是并行的内存分配将在large_pool，然而默认此参数为false，是否意味着并行所需要的内存是从shared_pool中分配的呢？怎么去验证这个内存的分配。
下面是10.2的中对PARALLEL_AUTOMATIC_TUNING解释。

When PARALLEL_AUTOMATIC_TUNING is set to true, Oracle determines the default values for parameters that control parallel execution. In addition to setting this parameter, you must specify the PARALLEL clause for the target tables in the system. Oracle then tunes all subsequent parallel operations automatically.

If you used parallel execution in a previous release and are now enabling PARALLEL_AUTOMATIC_TUNING, then you should reduce the amount of memory allocated from the shared pool to account for the decreased demand on that pool. This memory will now be allocated from the large pool, and will be computed automatically if LARGE_POOL_SIZE is not specified.

As part of the automatic tuning, Oracle will enable the PARALLEL_ADAPTIVE_MULTI_USER parameter. You can override any of the system-provided defaults if desired.

Maclean Liu(刘相兵

paralel_automatic_tuning==> 差不多是个废参数

Maclean Liu(刘相兵

_PX_use_large_pool
FALSE
Use Large Pool as source of PX buffers

- possible actions include

- increase _parallel_min_message_pool

- if shared_pool is heavily loaded

(the messages are normally stored there) then

- increase shared pool and/or tune shared pool usage

- set _PX_use_large_pool or parallel_automatic_tuning

so that we allocate out of the large pool

qq7343696

非常感谢ml，原来一直没有注意这个东西。