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Autor: Amir Taaki
Data:  
Para: libbitcoin
Assunto: Re: [Libbitcoin] obworker uses up all memory and crashes [WAS: Re: New releases for libbitcoin/Obelisk/sx]
As a programmer writing systems code targetting servers, I have to make
tradeoffs to better serve configurations/uses/scenarios over others.
I'm of the view that for old style HDDs are obsolete on servers,
especially for databases, network apps, ... anything doing disk IO.

Seek times of SSDs are basically zero. To jump around a file is no
longer costly (think of HDDs like VCRs and SSDs like DVDs), so many
things change with how you optimise your software. An example, a large
part of LevelDBs design/activity is about locating data close together
to minimise head movement. The semantics of SSDs on the OS layer are
different too.

This is why libbitcoin doesn't work so well on HDDs. If we can find a
way to make it perform better without significantly comprimising
elegance, and without comprimising on SSD performance then it should be
fixed. But I don't think it's a good idea to loose too much sleep over it.

Especially since consumer SSDs are wildly popular and dropping in price
fast. With the advent of new affordable high-end DRAM SSDs entering the
market, I expect to see a further drop in the price of SSDs.

http://www.techpowerup.com/188507/crossbar-unveils-resistive-ram-non-volatile-memory-technology.html

libbitcoin is a design for tomorrow; solving yesterday’s problems today
is for slow-moving leviathans.

On 08/01/14 15:51, mlmikael wrote:
> Aha.
>
>
>
> So what's the way to a "clean" (as in, robust/non-leaky) feedback
> mechanism for making earlier parts degrade gracefully and stop adding
> more work, when the buffer is full/close to full?
>
>
>
>
>
> Again thank you for the libbitcoin, it's basically essential to the
> Bitcoin world and may be the primary implementation if you look at it
> really.
>
>
>
> On 2014-01-08 11:42, Amir Taaki wrote:
>
>> Not really, and it doesn't seem like a good solution (more of a
>> workaround) now I'm thinking.
>>
>> The problem (if this is it), is that the block writer is IO bound, and
>> blocks are being queued such that memory is exhausted before writes can
>> complete.
>>
>> I'm not sure if it is the problem, but certainly should be something
>> along these lines if it's only caused by HDD.
>>
>> Only 500 blocks are downloaded at a time and attempted to be stored.
>>
>
>
>
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