Friday, July 25, 2008

Re: [HACKERS] Research/Implementation of Nested Loop Join optimization

Ron Mayer <rm_pg@cheapcomplexdevices.com> writes:
> Tom Lane wrote:
>> A backwards scan will get no such overlapping and thus be up to 2X
>> slower, unless the kernel is smart enough to do read-ahead for
>> descending-order read requests. Which seems not too probable.

> Linux's old adaptive readahead patches claimed to[1]:

I didn't say that there were *no* platforms that could do it.

regards, tom lane

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