Re: best way to invoke parallel in DW loads?

  • From: Martin Berger <martin.a.berger@xxxxxxxxx>
  • To: Dave.Herring@xxxxxxxxxx
  • Date: Wed, 16 Sep 2009 15:46:51 +0200

Dave,

just a small correction:
(at least in 11.1.0.7, have not tested 10gR2) these parameters are
calculated from CPU_COUNT:


__db_cache_size
__shared_pool_size
_cursor_db_buffers_pinned
_db_block_buffers
_db_block_lru_latches
_enqueue_hash_chain_latches
_enqueue_locks
_flashback_generation_buffer_size
_kghdsidx_count
_log_parallelism_max
_log_simultaneous_copies
_num_longop_child_latches
_parallel_min_message_pool
_shared_server_num_queues
_small_table_threshold
_spin_count
_sqlmon_max_plan
cpu_count
db_writer_processes
log_buffer
parallel_max_servers

- see also 
http://berxblog.blogspot.com/2009/01/instance-parameters-derived-from.html

> CPU_COUNT -> please don't change this.  Let Oracle figure it out.  In 10g 
> it's an underscore parameter and it doesn't make much sense to mess with it. 
>  The only impact that a manual change will have (I believe) is the default 
> parallel degree, calculated by CPU_COUNT * PARALLEL_THREADS_PER_CPU.

Neil, if you want to tweek there, be careful and make good records
about all related changes for tracability.

hth
 Martin
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