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fix: 공통 추천 목록의 오래된 인메모리 캐시 제거 #800

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Merged
Hexeong merged 2 commits into from
Jun 27, 2026
Merged

fix: 공통 추천 목록의 오래된 인메모리 캐시 제거 #800

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4f763ed
fix: 공통 추천 목록의 오래된 인메모리 캐시 제거
Hexeong Jun 26, 2026
30c579b
fix: 공통 추천 캐시 키에 학기명 포함
Hexeong Jun 26, 2026
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31 changes: 18 additions & 13 deletions .../com/example/solidconnection/university/service/GeneralUnivApplyInfoRecommendService.java
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Expand Up @@ -2,36 +2,41 @@

import static com.example.solidconnection.university.service.UnivApplyInfoRecommendService.RECOMMEND_UNIV_APPLY_INFO_NUM;

import com.example.solidconnection.term.repository.TermRepository;
import com.example.solidconnection.cache.annotation.ThunderingHerdCaching;
import com.example.solidconnection.university.domain.UnivApplyInfo;
import com.example.solidconnection.university.dto.UnivApplyInfoPreviewResponse;
import com.example.solidconnection.university.dto.UnivApplyInfoRecommendsResponse;
import com.example.solidconnection.university.repository.UnivApplyInfoRepository;
import java.util.List;
import lombok.Getter;
import lombok.RequiredArgsConstructor;
import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.context.event.EventListener;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
@RequiredArgsConstructor
public class GeneralUnivApplyInfoRecommendService {

private static final long GENERAL_RECOMMEND_CACHE_TTL_SEC = 3600;

/*
* 해당 시기에 열리는 대학교들 중 랜덤으로 선택해서 목록을 구성한다.
* */
private final UnivApplyInfoRepository univApplyInfoRepository;
private final TermRepository termRepository;

@Getter
private List<UnivApplyInfo> generalRecommends;
@Transactional(readOnly = true)
@ThunderingHerdCaching(
key = "university:recommend:general:{0}:{1}",
cacheManager = "customCacheManager",
ttlSec = GENERAL_RECOMMEND_CACHE_TTL_SEC

@chatgpt-codex-connector chatgpt-codex-connector Bot Jun 26, 2026

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P2 Badge Recompute cached recommendations instead of extending stale values

For this @ThunderingHerdCaching cache, ttlSec does not bound staleness under traffic: ThunderingHerdCachingAspect.refreshCache handles the last-10%-of-TTL path by calling getAndExpire and returning cachedValue, not by proceeding to rebuild from DB. When a popular /univ-apply-infos/recommend key is hit near expiry, a deleted or updated university can keep being served indefinitely unless an explicit prefix eviction runs, so the new 1-hour TTL does not provide the intended freshness window.

Useful? React with 👍 / 👎.

@Hexeong Hexeong Jun 26, 2026 •
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해당 부분은 별도로 #801 에서 작업할 예정입니다 :)

)
public UnivApplyInfoRecommendsResponse getGeneralRecommends(long termId, String termName) {
Pageable page = PageRequest.of(0, RECOMMEND_UNIV_APPLY_INFO_NUM);
List<UnivApplyInfo> generalRecommends = univApplyInfoRepository.findRandomByTermId(termId, page);

@EventListener(ApplicationReadyEvent.class)
public void init() {
termRepository.findByIsCurrentTrue().ifPresent(term -> {
Pageable page = PageRequest.of(0, RECOMMEND_UNIV_APPLY_INFO_NUM);
generalRecommends = univApplyInfoRepository.findRandomByTermId(term.getId(), page);
});
return new UnivApplyInfoRecommendsResponse(generalRecommends.stream()
.map(univApplyInfo -> UnivApplyInfoPreviewResponse.of(univApplyInfo, termName))
.toList());
}
}
36 changes: 25 additions & 11 deletions ...in/java/com/example/solidconnection/university/service/UnivApplyInfoRecommendService.java
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Expand Up @@ -2,7 +2,6 @@

import static com.example.solidconnection.common.exception.ErrorCode.CURRENT_TERM_NOT_FOUND;

import com.example.solidconnection.cache.annotation.ThunderingHerdCaching;
import com.example.solidconnection.common.exception.CustomException;
import com.example.solidconnection.term.domain.Term;
import com.example.solidconnection.term.repository.TermRepository;
Expand Down Expand Up @@ -47,17 +46,37 @@ public UnivApplyInfoRecommendsResponse getPersonalRecommends(long siteUserId) {

// 맞춤 추천 대학교의 수가 6개보다 적다면, 일반 추천 대학교를 부족한 수 만큼 불러온다.
if (trimmedRecommends.size() < RECOMMEND_UNIV_APPLY_INFO_NUM) {
trimmedRecommends.addAll(getGeneralRecommendsExcludingSelected(trimmedRecommends));
return new UnivApplyInfoRecommendsResponse(getPersonalRecommendPreviewsWithGeneralFallback(trimmedRecommends, term));
}

return new UnivApplyInfoRecommendsResponse(trimmedRecommends.stream()
.map(univApplyInfo -> UnivApplyInfoPreviewResponse.of(univApplyInfo, term.getName()))
.toList());
}

private List<UnivApplyInfo> getGeneralRecommendsExcludingSelected(List<UnivApplyInfo> alreadyPicked) {
List<UnivApplyInfo> generalRecommend = new ArrayList<>(generalUnivApplyInfoRecommendService.getGeneralRecommends());
generalRecommend.removeAll(alreadyPicked);
private List<UnivApplyInfoPreviewResponse> getPersonalRecommendPreviewsWithGeneralFallback(
List<UnivApplyInfo> personalRecommends,
Term term
) {
List<UnivApplyInfoPreviewResponse> recommendPreviews = new ArrayList<>(personalRecommends.stream()
.map(univApplyInfo -> UnivApplyInfoPreviewResponse.of(univApplyInfo, term.getName()))
.toList());
recommendPreviews.addAll(getGeneralRecommendsExcludingSelected(personalRecommends, term));

return recommendPreviews;
}

private List<UnivApplyInfoPreviewResponse> getGeneralRecommendsExcludingSelected(
List<UnivApplyInfo> alreadyPicked,
Term term
) {
List<Long> alreadyPickedIds = alreadyPicked.stream()
.map(UnivApplyInfo::getId)
.toList();
List<UnivApplyInfoPreviewResponse> generalRecommend = new ArrayList<>(generalUnivApplyInfoRecommendService
.getGeneralRecommends(term.getId(), term.getName())
.recommendedUniversities());
generalRecommend.removeIf(univApplyInfo -> alreadyPickedIds.contains(univApplyInfo.id()));
Collections.shuffle(generalRecommend);
int needed = RECOMMEND_UNIV_APPLY_INFO_NUM - alreadyPicked.size();
return generalRecommend.subList(0, Math.min(needed, generalRecommend.size()));
Expand All @@ -67,15 +86,10 @@ private List<UnivApplyInfo> getGeneralRecommendsExcludingSelected(List<UnivApply
* 공통 추천 대학교를 불러온다.
* */
@Transactional(readOnly = true)
@ThunderingHerdCaching(key = "university:recommend:general", cacheManager = "customCacheManager", ttlSec = 86400)
public UnivApplyInfoRecommendsResponse getGeneralRecommends() {
Term term = termRepository.findByIsCurrentTrue()
.orElseThrow(() -> new CustomException(CURRENT_TERM_NOT_FOUND));

List<UnivApplyInfo> generalRecommends = new ArrayList<>(generalUnivApplyInfoRecommendService.getGeneralRecommends());

return new UnivApplyInfoRecommendsResponse(generalRecommends.stream()
.map(univApplyInfo -> UnivApplyInfoPreviewResponse.of(univApplyInfo, term.getName()))
.toList());
return generalUnivApplyInfoRecommendService.getGeneralRecommends(term.getId(), term.getName());
}
}
89 changes: 72 additions & 17 deletions .../example/solidconnection/university/service/GeneralUnivApplyInfoRecommendServiceTest.java
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Expand Up @@ -4,11 +4,15 @@
import static org.assertj.core.api.Assertions.assertThat;
import static org.junit.jupiter.api.Assertions.assertAll;

import com.example.solidconnection.cache.manager.CustomCacheManager;
import com.example.solidconnection.support.TestContainerSpringBootTest;
import com.example.solidconnection.term.domain.Term;
import com.example.solidconnection.term.fixture.TermFixture;
import com.example.solidconnection.university.domain.UnivApplyInfo;
import com.example.solidconnection.university.dto.UnivApplyInfoPreviewResponse;
import com.example.solidconnection.university.dto.UnivApplyInfoRecommendsResponse;
import com.example.solidconnection.university.fixture.UnivApplyInfoFixture;
import com.example.solidconnection.university.repository.UnivApplyInfoRepository;
import java.util.List;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.DisplayName;
Expand All @@ -25,39 +29,90 @@ class GeneralUnivApplyInfoRecommendServiceTest {
@Autowired
private UnivApplyInfoFixture univApplyInfoFixture;

@Autowired
private UnivApplyInfoRepository univApplyInfoRepository;

@Autowired
private CustomCacheManager cacheManager;

@Autowired
private TermFixture termFixture;

private Term term;
private List<UnivApplyInfo> currentTermUnivApplyInfos;

@BeforeEach
void setUp() {
term = termFixture.현재_학기("2025-2");
cacheManager.evictUsingPrefix("university:recommend:general:" + term.getId());

univApplyInfoFixture.괌대학_A_지원_정보(term.getId());
univApplyInfoFixture.버지니아공과대학_지원_정보(term.getId());
univApplyInfoFixture.네바다주립대학_라스베이거스_지원_정보(term.getId());
univApplyInfoFixture.메모리얼대학_세인트존스_A_지원_정보(term.getId());
univApplyInfoFixture.서던덴마크대학교_지원_정보(term.getId());
univApplyInfoFixture.코펜하겐IT대학_지원_정보(term.getId());
univApplyInfoFixture.그라츠대학_지원_정보(term.getId());
univApplyInfoFixture.그라츠공과대학_지원_정보(term.getId());
univApplyInfoFixture.린츠_카톨릭대학_지원_정보(term.getId());
univApplyInfoFixture.메이지대학_지원_정보(term.getId());
generalUnivApplyInfoRecommendService.init();
currentTermUnivApplyInfos = List.of(
univApplyInfoFixture.괌대학_A_지원_정보(term.getId()),
univApplyInfoFixture.버지니아공과대학_지원_정보(term.getId()),
univApplyInfoFixture.네바다주립대학_라스베이거스_지원_정보(term.getId()),
univApplyInfoFixture.메모리얼대학_세인트존스_A_지원_정보(term.getId()),
univApplyInfoFixture.서던덴마크대학교_지원_정보(term.getId()),
univApplyInfoFixture.코펜하겐IT대학_지원_정보(term.getId())
);
}
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@Test
void 모집_시기의_대학_지원_정보_중에서_랜덤하게_N개를_추천_목록으로_구성한다() {
// when
UnivApplyInfoRecommendsResponse response = generalUnivApplyInfoRecommendService.getGeneralRecommends(
term.getId(),
term.getName()
);
List<Long> currentTermUnivApplyInfoIds = currentTermUnivApplyInfos.stream()
.map(UnivApplyInfo::getId)
.toList();

// then
assertAll(
() -> assertThat(response.recommendedUniversities()).hasSize(RECOMMEND_UNIV_APPLY_INFO_NUM),
() -> assertThat(response.recommendedUniversities())
.extracting(UnivApplyInfoPreviewResponse::id)
.isSubsetOf(currentTermUnivApplyInfoIds)
);
}

@Test
void 캐시를_삭제하면_서버_재기동_없이_DB_기준으로_추천_목록을_다시_구성한다() {
// given
List<UnivApplyInfo> universities = generalUnivApplyInfoRecommendService.getGeneralRecommends();
UnivApplyInfo deletedUnivApplyInfo = currentTermUnivApplyInfos.get(0);
UnivApplyInfoRecommendsResponse cachedResponse = generalUnivApplyInfoRecommendService.getGeneralRecommends(
term.getId(),
term.getName()
);

univApplyInfoRepository.delete(deletedUnivApplyInfo);
UnivApplyInfo addedUnivApplyInfo = univApplyInfoFixture.그라츠대학_지원_정보(term.getId());

// when
UnivApplyInfoRecommendsResponse responseBeforeCacheEvict = generalUnivApplyInfoRecommendService.getGeneralRecommends(
term.getId(),
term.getName()
);
cacheManager.evictUsingPrefix("university:recommend:general:" + term.getId());
UnivApplyInfoRecommendsResponse responseAfterCacheEvict = generalUnivApplyInfoRecommendService.getGeneralRecommends(
term.getId(),
term.getName()
);

// when & then
// then
assertAll(
() -> assertThat(universities)
.extracting("termId")
.allMatch(term.getId()::equals),
() -> assertThat(universities).hasSize(RECOMMEND_UNIV_APPLY_INFO_NUM)
() -> assertThat(cachedResponse.recommendedUniversities())
.extracting(UnivApplyInfoPreviewResponse::id)
.contains(deletedUnivApplyInfo.getId()),
() -> assertThat(responseBeforeCacheEvict.recommendedUniversities())
.extracting(UnivApplyInfoPreviewResponse::id)
.contains(deletedUnivApplyInfo.getId())
.doesNotContain(addedUnivApplyInfo.getId()),
() -> assertThat(responseAfterCacheEvict.recommendedUniversities())
.hasSize(RECOMMEND_UNIV_APPLY_INFO_NUM)
.extracting(UnivApplyInfoPreviewResponse::id)
.contains(addedUnivApplyInfo.getId())
.doesNotContain(deletedUnivApplyInfo.getId())
);
}
}
11 changes: 4 additions & 7 deletions ...ava/com/example/solidconnection/university/service/UnivApplyInfoRecommendServiceTest.java
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Expand Up @@ -78,7 +78,6 @@ void setUp() {
univApplyInfoFixture.그라츠공과대학_지원_정보(term.getId());
univApplyInfoFixture.린츠_카톨릭대학_지원_정보(term.getId());
univApplyInfoFixture.메이지대학_지원_정보(term.getId());
generalUnivApplyInfoRecommendService.init();
}

@Test
Expand Down Expand Up @@ -148,9 +147,8 @@ void setUp() {
assertThat(response.recommendedUniversities())
.hasSize(RECOMMEND_UNIV_APPLY_INFO_NUM)
.containsExactlyInAnyOrderElementsOf(
generalUnivApplyInfoRecommendService.getGeneralRecommends().stream()
.map(univApplyInfo -> UnivApplyInfoPreviewResponse.of(univApplyInfo, term.getName()))
.toList()
generalUnivApplyInfoRecommendService.getGeneralRecommends(term.getId(), term.getName())
.recommendedUniversities()
);
}

Expand All @@ -163,9 +161,8 @@ void setUp() {
assertThat(response.recommendedUniversities())
.hasSize(RECOMMEND_UNIV_APPLY_INFO_NUM)
.containsExactlyInAnyOrderElementsOf(
generalUnivApplyInfoRecommendService.getGeneralRecommends().stream()
.map(univApplyInfo -> UnivApplyInfoPreviewResponse.of(univApplyInfo, term.getName()))
.toList()
generalUnivApplyInfoRecommendService.getGeneralRecommends(term.getId(), term.getName())
.recommendedUniversities()
);
}
}
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