Re: PG-related ACM Article: "The Pathologies of Big Data"

From: Pierre Frédéric Caillaud <lists(at)peufeu(dot)com>
To: "Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com>, "Scott Carey" <scott(at)richrelevance(dot)com>
Cc: "Josh Kupershmidt" <schmiddy(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: PG-related ACM Article: "The Pathologies of Big Data"
Date: 2009-08-08 09:26:34
Message-ID: op.uyb66kq6cke6l8@soyouz
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>> I don't see how on any recent hardware, random access to RAM is slower
>> than
>> sequential from disk.  RAM access, random or not, is measured in
>> GB/sec...
>
> I don't think anybody's arguing that.

http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2795&p=5

These guys mention about 50 ns memory latency ; this would translate into
20 million memory "seeks" per second, which is in the same ballpark as the
numbers given by the article...

If you count 10GB/s bandwidth, 50 ns is the time to fetch 500 bytes.

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