Re: Sorting Tuples

Good job... even if it requires 10GB more of disk space (5GB for the
unpatched and 5GB for the patched result) and multiplying by 3 or 4 the
time needed to scan a 5GB table (twice for producing the sorted result
and once or twice in order to produce the diff).

Till now it's the candidate method: I could run it ad night while I'm
sleeping!

Thank you Ken!


On Thu, 2008-03-13 at 07:32 -0500, Kenneth Marshall wrote:
> Run the same query on an un-patched version and diff the output.
>
> Ken
>
> On Thu, Mar 13, 2008 at 12:25:53PM +0100, Manolo wrote:
> > Hi to all.
> >
> > INTRODUCTION:
> > I created a patch for PostgreSQL even if i'm not a PostgreSQL user. I
> > just wanted to implement an idea for possibly getting better External
> > Sorting module on PostgreSQL just using some basic C programming
> > knowledge and now I'm facing to using PostgreSQL for a while in order to
> > test my patch.
> > My patch "activates" when user is trying to sort a load of data more or
> > less twice bigger than his available memory (e.g.: sorting 5GB of data
> > just disposing of 1GB of available memory)
> >
> > PROBLEM:
> > First of all I want to realise my patch does sorts correctly or not. But
> > it's a little bit difficult to check when
> >
> >     SELECT * FROM huge_table ORDER BY a_column_of_huge_table;
> >
> > means checking a 4 or 5 GB result...
> >
> > QUESTION:
> > Is there a way to discover if data is sorted correctly other than
> > spending 2 months taking a look to the 5 GB result tuples, one by one?
> >
> > Thanks for your attention.
> > Regards, Manolo.
> >
> >
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