Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl Monk, Perl Meditation
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
Yes (tilly), I see. I read at Sleepycat that B-tree wins over hash, and then (if/when prescaled B-tree size exceeded) the hash wins again, but that sounds like just doing it wrong. I bow to your experience.

My gut instinct was to leave all seeking and logic to a trigger in the DB, but say we just use Perl - how to get more detailed profiling info to find the culprit? We don't have info about these objects but how about the general case..

I thought about the cache digest bitmap in Sourceforge squid docs, which uses 1 bit is used per object. This led me to imagine using a sequential memory map for 2 million objects, each of which contains address of parent and some other data. But realized locality in B-tree must beat this..

Any ideas as to performance if you

1) maintained memory map with Inline::C function which includes address of parent, an access counter, and a couple extra bytes. say 16MB for map plus an 8MB pool of free addresses. (or is this moot due to locality win in B-tree)
or
2) skip the memory map, but also
a) maintain a medium size B-tree of popular object MD5s, which are found because a counter in each object is incremented on seek. Added to populars tree when exceeding a pretuned threshold., hopefully this is searched very frequently instead of the big tree.
and
b) maintain a small hash to cache last X number of objects and cut churn.


In reply to Re: Performance quandary by mattr
in thread Performance quandary by SwellJoe

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!
  • 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 musing on the Monastery: (6)
    As of 2015-07-07 11:23 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (88 votes), past polls