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In our production environment ,a 2 nodes 11.2.0.4 rac ,the parameter parallel_force_local=true is set.
one sql use hint parallel ie: SELECT /*+ PARALLEL(t1 8) */ .in sql execute plan we found Parallel Execution on 2 instance
Parallel Execution Details (DOP=8 , Servers Allocated=8)
Instances : 2
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| Instance | Name | Type | Server# | Elapsed |
| | | | | Time(s) |
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| 2 | PX Coordinator | QC | | 0.01 |
| 1 | p000 | Set 1 | 1 | 7.31 |
| 1 | p001 | Set 1 | 2 | 7.28 |
| 1 | p002 | Set 1 | 3 | 7.39 |
| 1 | p003 | Set 1 | 4 | 7.53 |
| 2 | p001 | Set 1 | 6 | 7.43 |
| 2 | p002 | Set 1 | 7 | 7.36 |
| 2 | p003 | Set 1 | 8 | 7.36 |
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parallel_force_local=true is not useable?
and Connor said...
There were a number of issues way back in 11.2.0.4 with force local.
For example, if statement queueing was used, then it might choose to ignore the setting once the task reached the top of the queue etc.
Bottom line - if you're using software over a decade old and out of support...then you can hit challenges.
A potential workaround is use srvctl to create a single-instance service, and for your jobs that want to run in parallel, make them use that service.