Out of Memory when using spring-boot-starter-webflux

[andrescallev]

Integration

sentry-spring-boot-starter-jakarta

Java Version

21

Version

8.20.0

Steps to Reproduce

Currently using spring boot 3.5.5

And having the dependencies

• spring-boot-starter-webflux

• sentry-spring-boot-starter-jakarta (8.20.0)

• sentry-logback (8.20.0)

yml configuration for sentry:
sentry: enabled: false dsn: ${SENTRY_DSN} send-default-pii: true environment: ${spring.profiles.active} release: '@project.version@' tracesSampleRate: 0.1 logging: enabled: true minimum-event-level: ERROR

We have a microservice that consumes events from Azure Event Hub and Kafka with Spring Cloud Streams, and some flows sends HTTP requests with an org.springframework.web.reactive.function.client.WebClient;.

With those dependencies once you startup the API the memory increase until reach the top of memory allocated
We increased the memory limit to 3.5G and it used all

Sentry SDK starts to consumes all the memory with reactor objects

The solution that we found was to
@SpringBootApplication( exclude = { io.sentry.spring.boot.jakarta.SentryWebfluxAutoConfiguration.class } )

And
`
@configuration
@ConditionalOnProperty(name = "sentry.enabled", havingValue = "true")
public class SentryConfig {

@PostConstruct
public void configureSentryMemoryOptimization() {
Sentry.init(sentryOptions -> {
sentryOptions.setEnableExternalConfiguration(true);
});
}
}
`

With that we ensured to not automatically configure sentry, but programmatically take the configurations from the yml

Expected Result

With the regular yml configurations and the dependencies used without any programmatically change or any exclusion

Sentry must report errors to the dsn without use all the memory allocated

Actual Result

Sentry was consuming all memory doesn't matter

As is show the reactor instances the memory was increasing

But as result it consumes all memory

[linear]

JAVA-149 Out of Memory when using spring-boot-starter-webflux

[adinauer]

Thanks for reaching out @andrescallev, we'll try to reproduce.

[adinauer]

I was unable to reproduce so far. I started our Spring Boot 3 Webflux sample and then sent in ~26k requests using wrk -t8 -c20 -d30s -H "Authorization: Basic dXNlcjpwYXNzd29yZA==" http://127.0.0.1:8080/person/1.

Memory returned back to what appears normal to me after a couple manual GC invocations:

Are there any more details you could share or can you modify our sample to reproduce the issue?

Are you storing large amounts of data on global scope?

Looking into your thread dump should also allow you to check the chain of IScopes through each instances parentScopes property. Each IScopesalso has a creator String property, that gives a hint as to why the scopes were forked.

You can also check which of the IScope instances is consuming a lot of memory.

As an alternative, you could also give our OpenTelemetry integration a try. Here's some docs on that: https://docs.sentry.io/platforms/java/guides/spring-boot/opentelemetry/setup/

[andrescallev]

Hi @adinauer

We couldn't replicate it locally
The API is deployed in a kubernetes cluster

Other APIs with the same sentry, spring cloud streams dependencies versions but not the spring webflux one doesn't have this memory issue

In the image when we were troubleshooting the issue, the memory limit was 2GB

When we just disable sentry the memory consumption turns back to 600 MB max

checkout most of the POM with all dependencies used

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>3.5.5</version>
    <relativePath/>
  </parent>
  <groupId>com.org</groupId>
  <artifactId>xxx</artifactId>
  <version>1.0.0</version>
  <name>xxx</name>
  <description>xxx</description>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java.version>21</java.version>
    <spring-cloud-azure.version>5.19.0</spring-cloud-azure.version>
    <sentry.version>8.20.0</sentry.version>
    <jacoco.version>0.8.11</jacoco.version>
    <awaitility.version>4.1.1</awaitility.version>
    <pact.version>4.0.10</pact.version>
    <javafaker.version>1.0.2</javafaker.version>
    <cucumber.version>7.1.0</cucumber.version>
    <logback-version>8.1</logback-version>
    <spring-cloud.version>2025.0.0</spring-cloud.version>
    <kafka-avro-serializer.version>8.0.0</kafka-avro-serializer.version>
    <jedis.version>5.1.2</jedis.version>
    <querydsl.version>5.1.0</querydsl.version>
    <elastic-version>1.48.1</elastic-version>
    <mysql-jdbc.version>8.2.0</mysql-jdbc.version>
    <freemarker.version>2.3.34</freemarker.version>
    <podam.version>8.0.2.RELEASE</podam.version>
    <httpclient.version>5.4.3</httpclient.version>
    <nimbus-jose-jwt.version>10.0.2</nimbus-jose-jwt.version>
    <commons-compress.version>1.27.1</commons-compress.version>
    <commons-lang3.version>3.18.0</commons-lang3.version>
    <json-simple.version>1.1.1</json-simple.version>
    <json-path.version>2.9.0</json-path.version>
    <json-smart.version>2.5.2</json-smart.version>
    <assertj-joda-time.version>2.2.0</assertj-joda-time.version>
    <reporting-plugin.version>7.2.0</reporting-plugin.version>
    <codehaus.groovy.version>3.0.7</codehaus.groovy.version>
    <httpclient4.version>4.5.13</httpclient4.version>
    <xerces.version>2.12.2</xerces.version>
    <flapdoodle.embed.mongo.version>2.2.0</flapdoodle.embed.mongo.version>
    <classgraph.version>4.8.112</classgraph.version>
    <commons-io.version>2.16.1</commons-io.version>
    <commons-codec.version>1.16.0</commons-codec.version>
    <snakeyaml.version>2.0</snakeyaml.version>
    <sources.folder>src/main/java/xxx</sources.folder>
    <sonar.test.exclusions>src/test/**/*</sonar.test.exclusions>
    <sonar.projectKey>xxx</sonar.projectKey>
    <sonar.sources>src</sonar.sources>
    <sonar.projectName>xxx</sonar.projectName>
    <sonar.java.source>21</sonar.java.source>
    <sonar.sourceEncoding>UTF-8</sonar.sourceEncoding>
    <sonar.java.binaries>target</sonar.java.binaries>
    <sonar.exclusions>
      src/test/**/*,
      src/main/resources/templates/**/*,
      ${sources.folder}/infrastructure/configuration/**/*
    </sonar.exclusions>
    <sonar.coverage.exclusions>
      ${sources.folder}/xxx.java,
      ${sources.folder}/infrastructure/configuration/**/*
      ${sources.folder}/infrastructure/persistence/database/entity/**/*
    </sonar.coverage.exclusions>
    <sonar.coverage.jacoco.xmlReportPaths>
      ${project.basedir}/target/site/jacoco/jacoco.xml
    </sonar.coverage.jacoco.xmlReportPaths>
    <analysis.type>BUNDLE</analysis.type>
  </properties>

  <dependencies>

    <!-- Spring Boot dependencies -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-webflux</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-redis</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-oauth2-client</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-security</artifactId>
    </dependency>

    <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-oauth2-client</artifactId>
    </dependency>

    <dependency>
      <groupId>com.azure.spring</groupId>
      <artifactId>spring-cloud-azure-stream-binder-eventhubs</artifactId>
    </dependency>
    <dependency>
      <groupId>com.azure.spring</groupId>
      <artifactId>spring-cloud-azure-starter-storage-blob</artifactId>
    </dependency>
    <dependency>
      <groupId>com.azure.spring</groupId>
      <artifactId>spring-cloud-azure-starter-integration-storage-queue</artifactId>
    </dependency>
    <!-- Spring Boot dependencies -->

    <dependency>
      <groupId>co.elastic.apm</groupId>
      <artifactId>elastic-apm-agent</artifactId>
      <version>${elastic-version}</version>
    </dependency>
    <dependency>
      <groupId>com.nimbusds</groupId>
      <artifactId>nimbus-jose-jwt</artifactId>
      <version>${nimbus-jose-jwt.version}</version>
    </dependency>
    <dependency>
      <groupId>com.azure.spring</groupId>
      <artifactId>spring-cloud-azure-starter</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-compress</artifactId>
      <version>${commons-compress.version}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-lang3</artifactId>
      <version>${commons-lang3.version}</version>
    </dependency>
    <dependency>
      <groupId>com.googlecode.json-simple</groupId>
      <artifactId>json-simple</artifactId>
      <version>${json-simple.version}</version>
    </dependency>
    <dependency>
      <groupId>com.jayway.jsonpath</groupId>
      <artifactId>json-path</artifactId>
      <version>${json-path.version}</version>
    </dependency>
    <dependency>
      <groupId>net.minidev</groupId>
      <artifactId>json-smart</artifactId>
      <version>${json-smart.version}</version>
    </dependency>
    <dependency>
      <groupId>net.logstash.logback</groupId>
      <artifactId>logstash-logback-encoder</artifactId>
      <version>${logback-version}</version>
    </dependency>
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>commons-io</groupId>
      <artifactId>commons-io</artifactId>
      <version>${commons-io.version}</version>
    </dependency>
    <dependency>
      <groupId>commons-codec</groupId>
      <artifactId>commons-codec</artifactId>
      <version>${commons-codec.version}</version>
    </dependency>

    <!-- Sentry -->
    <dependency>
      <groupId>io.sentry</groupId>
      <artifactId>sentry-spring-boot-starter-jakarta</artifactId>
      <version>${sentry.version}</version>
    </dependency>
    <dependency>
      <groupId>io.sentry</groupId>
      <artifactId>sentry-logback</artifactId>
      <version>${sentry.version}</version>
    </dependency>
    <!-- Sentry -->

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>io.projectreactor</groupId>
      <artifactId>reactor-test</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-test</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.assertj</groupId>
      <artifactId>assertj-joda-time</artifactId>
      <version>${assertj-joda-time.version}</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.awaitility</groupId>
      <artifactId>awaitility</artifactId>
      <version>${awaitility.version}</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>com.github.javafaker</groupId>
      <artifactId>javafaker</artifactId>
      <version>${javafaker.version}</version>
      <exclusions>
        <exclusion>
          <groupId>org.yaml</groupId>
          <artifactId>snakeyaml</artifactId>
        </exclusion>
      </exclusions>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.yaml</groupId>
      <artifactId>snakeyaml</artifactId>
      <version>${snakeyaml.version}</version>
    </dependency>
    <dependency>
      <groupId>io.cucumber</groupId>
      <artifactId>cucumber-java</artifactId>
      <version>${cucumber.version}</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>io.cucumber</groupId>
      <artifactId>cucumber-spring</artifactId>
      <version>${cucumber.version}</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>me.jvt.cucumber</groupId>
      <artifactId>reporting-plugin</artifactId>
      <version>${reporting-plugin.version}</version>
    </dependency>
    <dependency>
      <groupId>au.com.dius</groupId>
      <artifactId>pact-jvm-provider-junit5-spring</artifactId>
      <version>${pact.version}</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.codehaus.groovy</groupId>
      <artifactId>groovy</artifactId>
      <version>${codehaus.groovy.version}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>${httpclient4.version}</version>
    </dependency>
    <dependency>
      <groupId>au.com.dius</groupId>
      <artifactId>pact-jvm-provider-spring</artifactId>
      <version>${pact.version}</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>au.com.dius</groupId>
      <artifactId>pact-jvm-consumer-java8</artifactId>
      <version>${pact.version}</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>xerces</groupId>
      <artifactId>xercesImpl</artifactId>
      <version>${xerces.version}</version>
    </dependency>
    <dependency>
      <groupId>au.com.dius</groupId>
      <artifactId>pact-jvm-consumer-junit5</artifactId>
      <version>${pact.version}</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>de.flapdoodle.embed</groupId>
      <artifactId>de.flapdoodle.embed.mongo</artifactId>
      <version>${flapdoodle.embed.mongo.version}</version>
      <scope>test</scope>
    </dependency>

    <!-- kafka avro serializer -->
    <dependency>
      <groupId>io.confluent</groupId>
      <artifactId>kafka-avro-serializer</artifactId>
      <version>${kafka-avro-serializer.version}</version>
    </dependency>
    <!-- kafka avro serializer -->

    <!-- querydsl -->
    <dependency>
      <groupId>com.querydsl</groupId>
      <artifactId>querydsl-apt</artifactId>
      <version>${querydsl.version}</version>
      <classifier>jakarta</classifier>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>com.querydsl</groupId>
      <artifactId>querydsl-jpa</artifactId>
      <classifier>jakarta</classifier>
      <version>${querydsl.version}</version>
    </dependency>

    <dependency>
      <groupId>io.github.classgraph</groupId>
      <artifactId>classgraph</artifactId>
      <version>${classgraph.version}</version>
    </dependency>
    <!-- querydsl -->

    <dependency>
      <groupId>com.mysql</groupId>
      <artifactId>mysql-connector-j</artifactId>
      <version>${mysql-jdbc.version}</version>
    </dependency>

    <dependency>
      <groupId>jakarta.persistence</groupId>
      <artifactId>jakarta.persistence-api</artifactId>
      <version>3.1.0</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>

    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-stream-binder-kafka</artifactId>
    </dependency>
    <dependency>
      <groupId>redis.clients</groupId>
      <artifactId>jedis</artifactId>
      <version>${jedis.version}</version>
    </dependency>

    <!-- freemarker -->
    <dependency>
      <groupId>org.freemarker</groupId>
      <artifactId>freemarker</artifactId>
      <version>${freemarker.version}</version>
    </dependency>
    <!-- freemarker -->

    <dependency>
      <groupId>uk.co.jemos.podam</groupId>
      <artifactId>podam</artifactId>
      <version>${podam.version}</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.apache.httpcomponents.client5</groupId>
      <artifactId>httpclient5</artifactId>
      <version>${httpclient.version}</version>
    </dependency>

  </dependencies>

  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>com.azure.spring</groupId>
        <artifactId>spring-cloud-azure-dependencies</artifactId>
        <version>${spring-cloud-azure.version}</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
      <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>${spring-cloud.version}</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <repositories>
    <repository>
      <id>confluent</id>
      <url>https://packages.confluent.io/maven/</url>
    </repository>
  </repositories>
  
</project>

This might help to have more context about the usages of the API