On 5 Feb, 14:04, "mkarb...@gmail.com" <mkarb...@gmail.com> wrote:
> On Feb 5, 6:45 am, "strawberry" <zac.ca...@gmail.com> wrote:
>
> > On 5 Feb, 09:28, Felix Geerinckx <felix.geerin...@gmail.com> wrote:
>
> > > "mkarb...@gmail.com" <mkarb...@gmail.com> wrote innews:1170638836.739194.95150@q2g2000cwa.googlegr oups.com:
>
> > > > I have a database of about 130 million records. I need to be able to
> > > > retrieve a random subset of those records (say random 100,000
> > > > records).
>
> > > Can you give some more info on the table structure?
>
> > > --
> > > felix
>
> > And just how slow IS 'prohibitively'?
>
> Table structure is very simple - a single table with about 20 columns
> in it (the database has already been normalized and there is no
> logical way to split it into multiple tables). Columns are either
> numeric or bit values. There are maybe 2 or 3 that are varchars but
> never longer than 10 characters.
>
> As for what is "prohibitively" slow, for a query where about 1.5
> million possible rows are returned (after the WHEREs are considered)
> it takes in excess of 15 minutes to return 100,000 rows even if I only
> try to return a single bit column.

Does MySQL actually say something like '100000 total, Query took 900
sec'?