Dear Ali,
A couple of comments. Indeed lots of energy is transferred into heat, but not
all. Therefore, using temperature (after calibrating specific heat coefficient
of the device ) is not a good method. Some energy is radiated as visible and
invisible light and hard to catch it all. Some as vibration. Some energy is
used to flip the bits on the disk. So to speak internal energy.
Thus, monitoring input power is the only way. However, since many jobs are
running, the results will be indeed inconsistent. Some people, therefore,
erroneously conclude that the question is not answerable. This is not true.
A properly crafted research proposal could get funding needed to accomplish
this fine goal. I expect 1 million US dollars for 5 years should be close to
sufficient. Make sure you measure how long SQLIte performs the task, record
power consumption in that period. Then run machine for the same period without
SQLIte. Difference in power consumption is what was due to SQLite, controlling
for the other processes. Obviously, caching and other things already mentioned,
will affect the numbers. Thus, you need to properly randomize these trials,
playing with their durations. You will have to perform many of these (therefore
5 year long project) to average out all fluctuations.
Given complexity of the project, you should consider getting initial funding to
design it in the first place and obtain preliminary data (and necessary
equipment) to justify and ensure future success. It appears, given your initial
email, that such funding is well underway towards being secured. Be sure to
control temperature and humanity in the room, because cooling fans also consume
energy, which depends on their speed and viscosity of the air. The tidal forces
(of the moon) will affect friction in bearings of all moving parts (fans,
disks). Be sure to either co-vary for them or randomize experiments for
different phases of the moon. DO NOT MOVE computer while experiment is running.
Coriolis force will affect friction in all rotating parts as well.
In summary, this is a perfectly doable experiment, if carefully planned and
executed. Radio astronomy easily reaches sensitivities of 10^{-9}. You can do
it too!
At conclusion of the 5 year research period, SQLite will be much different from
what it is today. So will kernels of operating systems, hardware etc.
Therefore, at conclusion of the research, you will have answered how much power
was consumed by SQLite 5 years ago. I am sure this will be very valuable piece
of information then, after all the money and efforts are spent. Because of this
short delay (5 years is short on the astronomical time scale) and because of
the experience you gained by conclusion of the project, I am rather certain you
will be able to obtain additional funding to continue and refine the answer to
the newer version of SQLite available then. The future is in your hands!
Roman
________________________________________
From: sqlite-users [[email protected]] on behalf of
Ali Dorri [[email protected]]
Sent: Tuesday, November 21, 2017 4:49 PM
To: Robert Oeffner
Cc: SQLite mailing list
Subject: Re: [sqlite] Energy consumption of SQLite queries
Dear All,
Thanks for your comments. That was really helpful.
Regards
Ali
On Tue, Nov 21, 2017 at 11:41 PM, Robert Oeffner <[email protected]> wrote:
> This is an interesting topic more belonging to the realms of information
> theory and statistical physics.
>
> I am not an expert in this area but from what I recall from undergraduate
> physics the moment you create order in one corner of the universe entropy
> rises in another place of the universe. If you loosely speaking equate
> information gathering such as an SQL query as creating order then that must
> have a cost in terms of increasing the entropy (heat in this case)
> elsewhere. There is a lower bound on how little entropy is generated during
> this process which comes down to the efficiency of the process (hardware
> and software in your case).
>
> One could get philosophical here and question whether mankinds computer
> modeling of climate change in itself causes the excess heat leading to
> global warming.
>
>
> Regards,
>
> Robert
>
>
> --
> Robert Oeffner, Ph.D.
> Research Associate,
> The Read Group, Department of Haematology,
> Cambridge Institute for Medical Research
> University of Cambridge
> Cambridge Biomedical Campus
> Wellcome Trust/MRC Building
> Hills Road
> Cambridge CB2 0XY
> www.cimr.cam.ac.uk/investigators/read/index.html
>
>
>
> Date: Tue, 21 Nov 2017 09:54:25 +1100
>> From: Ali Dorri <[email protected]>
>> To: SQLite mailing list <[email protected]>
>> Subject: [sqlite] Energy consumption of SQLite queries
>> Message-ID:
>> <[email protected]
>> ail.com>
>> Content-Type: text/plain; charset="UTF-8"
>>
>> Dear All,
>>
>> I am doing a research on the energy consumed by a query in SQLite. I have
>> a
>> program which fills a database with blocks of data. Then, it attempts to
>> remove some data from the database. I don't know how to measure the energy
>> consumed from my host, i.e., my laptop which has both the SQLite and the
>> program, from the time I generated the query till the query is finished
>> and
>> control returns back to my program.
>>
>> Any help is highly appreciated.
>>
>> Regards
>> Ali
>>
>>
>>
>
>
>
>
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