Groups > comp.os.linux.advocacy > #349401

Re: Algorithm to find data range

From	Sandman <mr@sandman.net>
Newsgroups	comp.os.linux.advocacy
Subject	Re: Algorithm to find data range
Date	2016-04-11 20:58 +0000
Message-ID	<sandman-b3b70fc4cbc0697fbcd2cb88cf7e38a7@individual.net> (permalink)
References	<negfcb$4ee$1@dont-email.me> <sandman-2ada1150bc27e3d11b868223a447a75e@individual.net> <hgjdke902.ata34p@rooftop.invalid>

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In article <hgjdke902.ata34p@rooftop.invalid>, owl wrote:

> > Sandman:
> > Also, given restriction 3 above, there is no way for you to know
> > what ID is at the middle of a sample. If you have 500k rows of
> > data, you'd think that ID 250,000 would be in the middle, but
> > since it was stipulated that ID could contain caps and not be
> > continuous, you may have cut two thirds up in the series. In fact,
> > ID 250,000 may be the very last ID according to rule #3. Or the
> > first, for that matter.
> 
> I took it to mean 500,000 items, not necessarily ID 1 - ID 500,000.

Exactly, meaning that the ID could be anything, and since we were supposed to 
fetch posts only by ID, it's impossible to fetch anything, right? For all we 
know, the ID's could be 1,982,827 to 3,462,987 with enough gaps in the ID's to 
amount ot 500,000 posts.

The only known variables are the number of posts, and that the posts have dates 
ranging from 2004-05-03 to 2014-05-03, right?

So, basically, the data could be:

2,765,982   2004-03-05
2,765,983   2004-03-05
2,765,984   2004-03-05
2,765,987   2004-03-05
..
4,756,234   2014-03-05

At this point it would be impossible to efficiently figure out what ID numbers 
correlate to what dates if we can't query what the first and last ID is.

I currently have 172,946 posts in my usenet table, and if I were interested in 
posts made between two dates, I would go:

: select * from usenet where date >= '2014-08-01' and date < '2014-09-01';

And I could get two posts back or several thousands, depending on traffic. And 
since the date field is indexed, the query takes 15ms (and returned 3,513 
posts).

-- 
Sandman

Thread

Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-11 11:23 -0400
  Re: Algorithm to find data range Sandman <mr@sandman.net> - 2016-04-11 17:09 +0000
    Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-11 19:25 +0000
      Re: Algorithm to find data range Sandman <mr@sandman.net> - 2016-04-11 20:58 +0000
        Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-11 17:38 -0400
          Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-11 18:11 -0400
            Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-11 22:25 +0000
          Re: Algorithm to find data range Sandman <mr@sandman.net> - 2016-04-12 06:16 +0000
        Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-11 21:46 +0000
          Re: Algorithm to find data range Sandman <mr@sandman.net> - 2016-04-12 07:18 +0000
            Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-12 08:15 +0000
              Re: Algorithm to find data range Sandman <mr@sandman.net> - 2016-04-12 10:34 +0000
            Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-12 13:32 -0400
              Re: Algorithm to find data range Steve Carroll <fretwizzer@gmail.com> - 2016-04-12 10:39 -0700
                Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-12 13:58 -0400
                Re: Algorithm to find data range Steve Carroll <fretwizzer@gmail.com> - 2016-04-12 11:59 -0700
    Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-11 23:23 -0400
      Re: Algorithm to find data range Sandman <mr@sandman.net> - 2016-04-12 07:14 +0000
      Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-12 10:44 +0000
        Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-12 15:17 +0000
          Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-13 17:15 -0400
            Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-13 22:23 +0000
              Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-13 18:32 -0400
                Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-14 04:33 +0000
                Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-14 05:51 +0000
                Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-14 20:15 -0400
                Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-15 01:18 +0000
        Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-12 13:25 -0400
          Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-12 19:08 +0000
    Re: Algorithm to find data range vallor <vallor@cultnix.org> - 2016-04-12 04:40 +0000
  Re: Algorithm to find data range owl <owl@rooftop.invalid> - 2016-04-11 18:06 +0000
  Re: Algorithm to find data range 7 <7@enemygadgets.com> - 2016-04-11 22:46 +0000
    Re: Algorithm to find data range Omar <omarsayeed@linuxmail.org> - 2016-04-11 18:52 -0400
      Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-12 13:28 -0400
        Re: Algorithm to find data range Omar <omarsayeed@linuxmail.org> - 2016-04-12 13:46 -0400
    Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-11 22:13 -0400
  Re: Algorithm to find data range Fabian Russell <fb@zen.info> - 2016-04-11 23:22 +0000
    Re: Algorithm to find data range vallor <vallor@cultnix.org> - 2016-04-12 00:06 +0000
      Re: Algorithm to find data range Omar <omarsayeed@linuxmail.org> - 2016-04-11 20:26 -0400
      Re: Algorithm to find data range Chris Ahlstrom <OFeem1987@teleworm.us> - 2016-04-12 05:30 -0400
      Re: Algorithm to find data range chrisv <chrisv@nospam.invalid> - 2016-04-12 06:50 -0500
    Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-11 22:34 -0400
      Re: Algorithm to find data range Fabian Russell <fb@zen.info> - 2016-04-12 09:25 +0000
        Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-12 13:32 -0400
  Is it your own personal NNTP/Usenet server ? Jeff-Relf.Me <@.> - 2016-04-11 16:32 -0700
    Re: Algorithm to find data range DFS <nospam@dfs.com> - 2016-04-12 12:47 -0400
      Re: Algorithm to find data range Peter Köhlmann <peter-koehlmann@t-online.de> - 2016-04-12 20:46 +0200
        Re: Algorithm to find data range chrisv <chrisv@nospam.invalid> - 2016-04-12 13:59 -0500
        Re: Algorithm to find data range Silver Slimer <linux@sucks.balls> - 2016-04-12 17:08 -0400
      My "newsReader" (X.ZIP) is also a console. Jeff-Relf.Me <@.> - 2016-04-12 12:27 -0700
      My "newsReader" (X.ZIP) is also a console. Jeff-Relf.Me <@.> - 2016-04-12 12:31 -0700

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