RE: ASMM - resizing triggers/thresholds

Nice direct measurement.  

Another method is to have a re-executable regression test and measure the polar cases nothing pinned versus everything pinned and the incremental n cases of selected pinning and simply report elapsed time and maximum shared pool occupied (or just elapsed time if the latter is too tricky in the environment).  

I have not done this in quite a while, but I was a bit surprised at how often “pin everything” won and by how much.  

Nice work Tanel!  

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Tanel Poder Sent: Monday, February 04, 2019 5:19 PM
To: Jonathan Lewis
Cc: Oracle-L Freelists; martin.klier_at_performing-db.com Subject: Re: ASMM - resizing triggers/thresholds  

Hi,  

In addition to what Jonathan said, here are my ramblings about what the KGL simulator is (and the buffer cache simulator uses similar logic) that is used for modeling "time saved reloading objects/blocks into cache if we hadn't kicked them out previously":  

https://blog.tanelpoder.com/2009/09/13/kgl-simulator-shared-pool-simulator-and-buffer-cache-simulator-what-are-these/  

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Tanel Poder

https://blog.tanelpoder.com/seminar/

 

On Sat, Feb 2, 2019 at 9:05 AM Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk> wrote:


Martin,

If you look for the hidden parameters like "%memory_broker%" that gives you some clues.
12.2.0.1

NAME                                          SES_VAL
--------------------------------------------- ------------------------------


_automemory_broker_interval                   3


_memory_broker_log_stat_entries               5

_memory_broker_marginal_utility_bc            12




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