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Reduce memory allocations in search. #8820

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merged 1 commit into from
Jun 19, 2025
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Reduce memory allocations in search. #8820

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37 changes: 24 additions & 13 deletions app/lib/search/mem_index.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -263,6 +263,13 @@ class InMemoryPackageIndex {
// extra item, that will be addressed after the ranking score is determined.
var totalCount = packageScores?.positiveCount() ?? predicateFilterCount;

// Checking if it is worth to calculate the sorted order, estimating the
// total count by overcounting the best name matches.
final maximumTotalCount = totalCount + (bestNameIndex != null ? 1 : 0);
if (maximumTotalCount < query.offset) {
return PackageSearchResult.empty();
}

Iterable<IndexedPackageHit> indexedHits;
switch (query.effectiveOrder) {
case SearchOrder.top:
Expand Down Expand Up @@ -512,33 +519,37 @@ class InMemoryPackageIndex {
return _TextResults(topApiPages);
}

List<IndexedPackageHit> _rankWithValues(
Iterable<IndexedPackageHit> _rankWithValues(
IndexedScore<String> score, {
// if the item count is fewer than this threshold, an empty list will be returned
required int requiredLengthThreshold,
// When no best name match is applied, this parameter will be `-1`
required int bestNameIndex,
}) {
final list = <IndexedPackageHit>[];
int compare(int aIndex, int bIndex) {
if (aIndex == bestNameIndex) return -1;
if (bIndex == bestNameIndex) return 1;
final aScore = score.getValue(aIndex);
final bScore = score.getValue(bIndex);
final scoreCompare = -aScore.compareTo(bScore);
if (scoreCompare != 0) return scoreCompare;
// if two packages got the same score, order by last updated
return _compareUpdated(_documents[aIndex], _documents[bIndex]);
}

final list = <int>[];
for (var i = 0; i < score.length; i++) {
final value = score.getValue(i);
if (value <= 0.0 && i != bestNameIndex) continue;
list.add(IndexedPackageHit(
i, PackageHit(package: score.keys[i], score: value)));
list.add(i);
}
if (requiredLengthThreshold > list.length) {
// There is no point to sort or even keep the results, as the search query offset ignores these anyway.
return [];
}
list.sort((a, b) {
if (a.index == bestNameIndex) return -1;
if (b.index == bestNameIndex) return 1;
final scoreCompare = -a.hit.score!.compareTo(b.hit.score!);
if (scoreCompare != 0) return scoreCompare;
// if two packages got the same score, order by last updated
return _compareUpdated(_documents[a.index], _documents[b.index]);
});
return list;
list.sort(compare);
return list.map((i) => IndexedPackageHit(
i, PackageHit(package: score.keys[i], score: score.getValue(i))));
}

List<IndexedPackageHit> _rankWithComparator(
Expand Down