Re: APR 1.0 released - Mailing list pgsql-hackers

Added to TODO:

* Consider parallel processing a single query
 This would involve using multiple threads or processes to do optimization, sorting, or execution of single query.  The
majoradvantage of such a feature would be to allow multiple CPUs to work together to process a single query.
 


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Jim C. Nasby wrote:
> Any chance of having query parallelization added to TODO? I'm guessing
> it will be a huge job, but it's also one of the places where the 'big 3'
> have a huge advantage in scalability.
> 
> On Mon, Sep 13, 2004 at 10:24:05AM -0700, Sailesh Krishnamurthy wrote:
> > >>>>> "CB" == Christopher Browne <cbbrowne@acm.org> writes:
> > 
> >     CB> futile discussions ask for it.  Notably, on an SMP system, it
> >     CB> would be a neat idea for complex queries involving joins to
> >     CB> split themselves so that different parts run in separate
> >     CB> threads.
> > 
> > You don't really need threads for this. All you need is to have
> > multiple backends and use queues to exchange tuples at specific
> > points. This is much like the Exchange operator in Volcano. 
> > 
> >     CB> The other Way, Way Cool part would be for queries that are
> >     CB> scanning big tables to split the scans into unions of partial
> >     CB> scans, so that on an 8 CPU box you'd take the "Big 4GB Table"
> >     CB> and have 8 threads simultaneously scanning different parts of
> >     CB> it.  (And making ARC all the more important :-).)
> > 
> > Again this can be done without threads .. you just need inter-process
> > communication. 
> > 
> > (BTW, there is at least one commercial system that follows exactly
> > this model).
> > 
> > -- 
> > Pip-pip
> > Sailesh
> > http://www.cs.berkeley.edu/~sailesh
> > 
> > 
> > 
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> 
> -- 
> Jim C. Nasby, Database Consultant               decibel@decibel.org 
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