Beefy Boxes and Bandwidth Generously Provided by pair Networks
Clear questions and runnable code
get the best and fastest answer
 
PerlMonks  

comment on

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

If you really want to do things by yourself ....

Get a honking big file, say 4GB, and a smaller file, say 4 MB.

To manipulate file 17623, seek location 17623 * 4 in the smaller file, and read in the 4 byte word you find there, call it <offset>. Seek location <offset> in the larger file, and read bytes until you reach the EOF marker. Alternately, you could store a 2 byte length in the index file.

If you need to enlarge file N, copy it to the end of the large file, where you can do whatever you want. You can keep an index of unused 'holes', and move files that fit into the hole instead of to the end of the file. When the file runs out of space, compact the file to a new file, generating a new index.

On the other hand, DB companies spend millions of dollars and devote hundreds of employees to maximize the efficiency of such operations. Can you really out-perform them?

--
TTTATCGGTCGTTATATAGATGTTTGCA


In reply to Re: Combining Ultra-Dynamic Files to Avoid Clustering (Ideas?) by TomDLux
in thread Combining Ultra-Dynamic Files to Avoid Clustering (Ideas?) by rjahrman

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



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

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

How do I use this? | Other CB clients
Other Users?
Others examining the Monastery: (2)
As of 2021-10-27 23:52 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    My first memorable Perl project was:







    Results (95 votes). Check out past polls.

    Notices?