Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl: the Markov chain saw
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

A trillion records? A trillion *bytes* is roughly 1TB. Let's assume that your records are, on average, 32 bytes - they're probably bigger, but that doesn't really matter. So you need to read 32TB, process it, and write 32TB. I don't think it's at all unreasonable to take 16 days for 64TB of I/O.

As you've been told, you need to profile your code. You actually need to do that for any performance problem, not just this one.

I, of course, have not profiled your code, and so everything from here on is mere speculation, but I bet that you are I/O bound. You have at least three places where I/O may be limiting you. Reading from the database (especially if you've only got one database server); transmitting data across the network from the database to the machine your perl code is running on; and writing the CSV back out. At least the first two of those can be minimised by partitioning the data and the workload and parallelising everything across multiple machines. You *may* be able to partition the data such that you can have seperate workers producing CSV files too.


In reply to Re: Processing ~1 Trillion records by DrHyde
in thread Processing ~1 Trillion records by aossama

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others romping around the Monastery: (4)
    As of 2020-08-08 04:35 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?
      Which rocket would you take to Mars?










      Results (51 votes). Check out past polls.

      Notices?