Thanks for sharing your ideas, Adrien~~
> 2021年7月2日 上午1:26，Adrien Grand <[email protected]> 写道：
>
> Hi,
>
> This is just a number that proved to work well in practice.
>
> The general idea is that we want to narrow down the set of candidates
> periodically in order to speed up query execution. If we do it too often,
> then we might spend more time narrowing down the set of candidates than
> actually evaluating candidates, and if we don't do it often enough, then
> we're still evaluating lots of candidates that have no chance of being
> competitive and the query is slow too. What the code samples you shared mean
> is that Lucene would only re-evaluate the set of candidates whenever it seems
> that we could reduce the number of candidates by 8x.
>
> On Thu, Jul 1, 2021 at 11:57 AM LuXugang <[email protected]> wrote:
> Hi,
>
> While reading Lucene source code, I have a tiny question about the selection
> of threshold：threshold = value >>> 3.
>
> eg. in NumericComparator#updateCompetitiveIterator(), as 'threshold =
> iteratorCost >>> 3' a condition for whether to update iterator
>
> eg. in IndexOrDocValuesQuery, as 'threshold = cost() >>> 3' a condition for
> choosing indexScorerSupplier or dvScorerSupplier
>
> So the selection of threshold base some theory or tradeoff or other reason?
>
> Could I get some suggestion？
>
>
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>
> --
> Adrien
