Bob Jones wrote:
> My current thinking is that the filter is a bit like an "fgrep" and
> the sort actually requires memory allocation and some "real work", and
> thus I've settled on the filter for now pending experiments with a
> larger quantity of data.
That's fine.
A top-1-sort is less work than you maybe think:
You go through all items and find the biggest one.
So there is one comparison operator per row - very similar to
what happens when "grepping" for NULL values.
Yours,
Laurenz Albe
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