From fa41595818eeb0d1da7f271a7f0554eb544fc6e3 Mon Sep 17 00:00:00 2001
From: Yanming Zhou <zhouyanming@gmail.com>
Date: Tue, 26 Jul 2022 09:38:12 +0800
Subject: [PATCH] Limit single finders max results to 2 for performance.

Closes #2594
Original pull request #2604
---
 .../jpa/repository/support/QuerydslJpaPredicateExecutor.java  | 2 +-
 .../data/jpa/repository/support/QuerydslJpaRepository.java    | 2 +-
 .../data/jpa/repository/support/SimpleJpaRepository.java      | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/QuerydslJpaPredicateExecutor.java b/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/QuerydslJpaPredicateExecutor.java
index c4f4b07b9..1de39e2c5 100644
--- a/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/QuerydslJpaPredicateExecutor.java
+++ b/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/QuerydslJpaPredicateExecutor.java
@@ -91,7 +91,7 @@ public class QuerydslJpaPredicateExecutor<T> implements QuerydslPredicateExecuto
 		Assert.notNull(predicate, "Predicate must not be null");
 
 		try {
-			return Optional.ofNullable(createQuery(predicate).select(path).fetchOne());
+			return Optional.ofNullable(createQuery(predicate).select(path).limit(2).fetchOne());
 		} catch (NonUniqueResultException ex) {
 			throw new IncorrectResultSizeDataAccessException(ex.getMessage(), 1, ex);
 		}
diff --git a/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/QuerydslJpaRepository.java b/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/QuerydslJpaRepository.java
index 3ef8c5db4..d082e65a6 100644
--- a/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/QuerydslJpaRepository.java
+++ b/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/QuerydslJpaRepository.java
@@ -101,7 +101,7 @@ public class QuerydslJpaRepository<T, ID extends Serializable> extends SimpleJpa
 	public Optional<T> findOne(Predicate predicate) {
 
 		try {
-			return Optional.ofNullable(createQuery(predicate).select(path).fetchOne());
+			return Optional.ofNullable(createQuery(predicate).select(path).limit(2).fetchOne());
 		} catch (NonUniqueResultException ex) {
 			throw new IncorrectResultSizeDataAccessException(ex.getMessage(), 1, ex);
 		}
diff --git a/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/SimpleJpaRepository.java b/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/SimpleJpaRepository.java
index 0b0125bc5..0927afc23 100644
--- a/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/SimpleJpaRepository.java
+++ b/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/SimpleJpaRepository.java
@@ -452,7 +452,7 @@ public class SimpleJpaRepository<T, ID> implements JpaRepositoryImplementation<T
 	public Optional<T> findOne(@Nullable Specification<T> spec) {
 
 		try {
-			return Optional.of(getQuery(spec, Sort.unsorted()).getSingleResult());
+			return Optional.of(getQuery(spec, Sort.unsorted()).setMaxResults(2).getSingleResult());
 		} catch (NoResultException e) {
 			return Optional.empty();
 		}
@@ -482,7 +482,7 @@ public class SimpleJpaRepository<T, ID> implements JpaRepositoryImplementation<T
 		try {
 			return Optional
 					.of(getQuery(new ExampleSpecification<>(example, escapeCharacter), example.getProbeType(), Sort.unsorted())
-							.getSingleResult());
+							.setMaxResults(2).getSingleResult());
 		} catch (NoResultException e) {
 			return Optional.empty();
 		}