django-\/\/ i K |

_PGA_MAX_SIZE

限制单个进程下所有工作区的大小 10gR2

pga_aggregate_target _PGA_MAX_SIZE
<1GB 200MB
1~4GB 20%*pga_aggregate_target
>=4GB 480MB

11gR2

pga_aggregate_target _PGA_MAX_SIZE
>=1GB 10%*pga_aggregate_target
<1GB max(20%*pga_aggregate_target,10m)

_SMM_MAX_SIZE

限制单个进程下单个工作区的最大大小

  • For values of PAT below 512 MB, _SMM_MAX_SIZE is 20% of PGA_AGGREGATE_TARGET.

  • For PAT values of 512 MB and beyond, _SMM_MAX_SIZE is always 50% of _PGA_MAX_SIZE.

  • In Oracle9i, _SMM_MAX_SIZE had a limit of 100 MB. Following is an example of a session

that had two simultaneously active work areas when the given parameters were in effect: MIN(5%PGA_AGGREGATE_TARGET,100M) 5%PGA_AGGREGATE即 _smm_max_size

  • P_A_T <=500MB  _smm_max_size =20%*P_A_T
  • P_A_T <=1000MB  _smm_max_size =100MB
  • P_A_T <=2560MB  _smm_max_size =10%*P_A_T
  • P_A_T >=2560MB  _smm_max_size =262060KB

_SMM_PX_MAX_SIZE

限制并行任务的所有工作区总大小 The setting of _SMM_PX_MAX_SIZE is always 50% of PGA_AGGREGATE_TARGET.

There is no limit on_SMM_PX_MAX_SIZE(at least not within the tested range of PGA_AGGREGATE_TARGET of 10 MB to 32 GB).

In Oracle9i, _SMM_PX_MAX_SIZE was 30% of PGA_AGGREGATE_TARGET. 30%*PGA_AGGREGATE_TARGET/DOP

  • DOP<=5  _smm_max_size 生效
  • DOP>5   _smm_px_max_size 生效