What enables Parallel Query
Hi, we detected in production that some started PQ-slaves worked, were busy, but no parallel-hint is given and the degree-val of all tables is 1. so what else could cause the switch to parallel query?
Thanks for advice
Read the article in http://asktom.oracle.com/pls/ask/f?p...:1432298995609 , maybe is the PQ automatically being used ??
What is the setting of these parameters for your database:
The following are features that will make the optimizer consider the use of a parallel plan for a query:
* Parallel hints i.e. /*+ PARALLEL(emp,5) */ (which you don't have)
* Parallel session setting e.g. Parameter parallel_automatic_tuning
& parallel_adaptive_multi_user. Somebody may have set these parameters for their sessions.
* Setting a degree of parallel and/or the number of instances on a table or index in a query.
OCP DBA (8,8i,9i)
"Let's document it and call it a feature."
Here the params :
But i detected an index in dba_indexes which has degree of 4
NAME TYPE VALUE
parallel_server 1 FALSE
parallel_server_instances 3 1
parallel_broadcast_enabled 1 FALSE
parallel_adaptive_multi_user 1 FALSE
parallel_threads_per_cpu 3 2
parallel_automatic_tuning 1 FALSE
optimizer_percent_parallel 3 0
parallel_min_percent 3 0
parallel_min_servers 3 0
parallel_max_servers 3 5
parallel_execution_message_size 3 2152
this could be the trouble-maker!
Thanks, in short there is all important for PQ.
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