docs: expand short-circuit explanation

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1028777 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Yonik Seeley 2010-10-29 14:42:33 +00:00
parent 7b53bdf808
commit 584d68f2e0
1 changed files with 5 additions and 0 deletions

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@ -177,6 +177,11 @@ class TopGroupCollector extends GroupCollector {
// if orderedGroups != null, then we already have collected N groups and
// can short circuit by comparing this document to the smallest group
// without having to even find what group this document belongs to.
// Even if this document belongs to a group in the top N, we know that
// we don't have to update that group.
//
// Downside: if the number of unique groups is very low, this is
// wasted effort as we will most likely be updating an existing group.
if (orderedGroups != null) {
for (int i = 0;; i++) {
final int c = reversed[i] * comparators[i].compareBottom(doc);