Re: Threaded Sorting

Hans-Jrgen Schnig wrote:
> Did anybody think about threaded sorting so far?
> Assume an SMP machine. In the case of building an index or in the case
> of sorting a lot of data there is just one backend working. Therefore
> just one CPU is used.
> What about starting a thread for every temporary file being created?
> This way CREATE INDEX could use many CPUs.
> Maybe this is worth thinking about because it will speed up huge
> databases and enterprise level computing.

We haven't thought about it yet because there are too many buggy thread
implementations. We are probably just now getting to a point where we
can consider it. However, lots of databases have moved to threads for
all sorts of things and ended up with a royal mess of code. Threads
can only improve things in a few areas of the backend so it would be
nice if we could limit the exposure to threads to those areas; sorting
could certainly be one of them, but frankly, I think disk I/O is our
limiting factore there. I would be interested to see some tests that
showed otherwise.

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