Add 'spring.r2dbc.pool.acquire-retry' property

Add a new property to configure the pool acquire retry value.

Closes gh-44017

Author: philwebb

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/r2dbc/ConnectionFactoryConfigurations.java

@@ -108,6 +108,7 @@ ConnectionPool connectionFactory(R2dbcProperties properties,
 				map.from(pool.getMaxIdleTime()).to(builder::maxIdleTime);
 				map.from(pool.getMaxLifeTime()).to(builder::maxLifeTime);
 				map.from(pool.getMaxAcquireTime()).to(builder::maxAcquireTime);
+				map.from(pool.getAcquireRetry()).to(builder::acquireRetry);
 				map.from(pool.getMaxCreateConnectionTime()).to(builder::maxCreateConnectionTime);
 				map.from(pool.getInitialSize()).to(builder::initialSize);
 				map.from(pool.getMaxSize()).to(builder::maxSize);

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/r2dbc/R2dbcProperties.java

@@ -158,6 +158,11 @@ public static class Pool {
 		 */
 		private Duration maxAcquireTime;
 
+		/**
+		 * Number of acquire retries if the first acquire attempt fails.
+		 */
+		private int acquireRetry = 1;
+
 		/**
 		 * Maximum time to validate a connection from the pool. By default, wait
 		 * indefinitely.
@@ -234,6 +239,14 @@ public void setMaxAcquireTime(Duration maxAcquireTime) {
 			this.maxAcquireTime = maxAcquireTime;
 		}
 
+		public int getAcquireRetry() {
+			return this.acquireRetry;
+		}
+
+		public void setAcquireRetry(int acquireRetry) {
+			this.acquireRetry = acquireRetry;
+		}
+
 		public Duration getMaxCreateConnectionTime() {
 			return this.maxCreateConnectionTime;
 		}

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/r2dbc/R2dbcAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,6 +35,7 @@
 import org.assertj.core.api.InstanceOfAssertFactory;
 import org.assertj.core.api.ObjectAssert;
 import org.junit.jupiter.api.Test;
+import reactor.core.publisher.Mono;
 
 import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
@@ -47,6 +48,7 @@
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.r2dbc.core.DatabaseClient;
+import org.springframework.test.util.ReflectionTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -82,8 +84,8 @@ void configureWithUrlAndPoolPropertiesApplyProperties() {
 		this.contextRunner
 			.withPropertyValues("spring.r2dbc.url:r2dbc:h2:mem:///" + randomDatabaseName(),
 					"spring.r2dbc.pool.max-size=15", "spring.r2dbc.pool.max-acquire-time=3m",
-					"spring.r2dbc.pool.min-idle=1", "spring.r2dbc.pool.max-validation-time=1s",
-					"spring.r2dbc.pool.initial-size=0")
+					"spring.r2dbc.pool.acquire-retry=5", "spring.r2dbc.pool.min-idle=1",
+					"spring.r2dbc.pool.max-validation-time=1s", "spring.r2dbc.pool.initial-size=0")
 			.run((context) -> {
 				assertThat(context).hasSingleBean(ConnectionFactory.class)
 					.hasSingleBean(ConnectionPool.class)
@@ -96,6 +98,9 @@ void configureWithUrlAndPoolPropertiesApplyProperties() {
 					assertThat(poolMetrics.getMaxAllocatedSize()).isEqualTo(15);
 					assertThat(connectionPool).hasFieldOrPropertyWithValue("maxAcquireTime", Duration.ofMinutes(3));
 					assertThat(connectionPool).hasFieldOrPropertyWithValue("maxValidationTime", Duration.ofSeconds(1));
+					Mono<?> create = (Mono<?>) ReflectionTestUtils.getField(connectionPool, "create");
+					assertThat(create.getClass().getName()).endsWith("MonoRetry");
+					assertThat(create).hasFieldOrPropertyWithValue("times", 5L);
 				}
 				finally {
 					connectionPool.close().block();