RE: best way to invoke parallel in DW loads?
- From: Amihay Gonen <Amihay.Gonen@xxxxxxxxxxx>
- To: "martin.a.berger@xxxxxxxxx" <martin.a.berger@xxxxxxxxx>, "Dave.Herring@xxxxxxxxxx" <Dave.Herring@xxxxxxxxxx>
- Date: Wed, 16 Sep 2009 16:54:00 +0300
In 11Gr2 this parameter can be used to CPU caging.
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Martin Berger
Sent: Wednesday, September 16, 2009 4:47 PM
To: Dave.Herring@xxxxxxxxxx
Cc: nkodner@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: Re: best way to invoke parallel in DW loads?
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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