configure spring.codec.max-in-memory-size When using ReactiveElasticsearchClient

or:

    final Consumer<ClientCodecConfigurer> consumer = configurer -> {
        final ClientCodecConfigurer.ClientDefaultCodecs codecs = configurer.defaultCodecs();
        codecs.maxInMemorySize(maxBufferMb * 1024 * 1024);
    };

    WebClient.builder().codecs(consumer).build();

As of Spring Boot 2.3.0, there is now a dedicated configuration property for the Reactive Elasticsearch REST client.

You can use the following configuration property to set a specific memory limit for the client.

spring.data.elasticsearch.client.reactive.max-in-memory-size=

The already existing spring.codec.max-in-memory-size property is separate and only affects other WebClient instances in the application.

Using the plain reaction WebClient I ran into the same issue (going from 2.1.9 to 2.2.1.) I had no luck setting spring.codec.max-in-memory-size and later found a hint that this wasn't the way to go anyway:

… On the client side, the limit can be changed in WebClient.Builder.

(source, including dead link :-S )

I still haven't found out where WebClient.Builder gets the default 256K limit¹. However, the following enabled me to raise the buffer size limit to 16M:

WebClient.builder()
  .…
  .exchangeStrategies(ExchangeStrategies.builder()
    .codecs(configurer -> configurer
      .defaultCodecs()
      .maxInMemorySize(16 * 1024 * 1024))
    .build())
  .build();

So, it seems to me (without knowing the intricacies of spring-data-elasticsearch) that if you can somehow get your hands on the WebClient as returned from the WebClientProvider you should be able to mutate it to include the ExchangeStrategies from above.

Perhaps you can provide your own override of DefaultWebClientProvider along the lines of (absolutely untested!):

class MyDefaultWebClientProvider extends DefaultWebClientProvider {
  @Override
  public WebClient get(InetSocketAddress endpoint) {
    return super.get(endpoint)
      .mutate() // Obtain WebClient.Builder instance.
      .exchangeStrategies(ExchangeStrategies.builder()
        .codecs(configurer -> configurer
          .defaultCodecs()
          .maxInMemorySize(16 * 1024 * 1024))
        .build())
      .build();
  }
}

YMMV.

---

UPDATE #1:

¹⁾ Now I found it. And it explains why setting spring.codec.max-in-memory-size has no effect; the property is hardcoded at 256K in the base class uses by all default codecs, cf. BaseDefaultCodecs.

A couple of days ago I implemented the possibility to customize the WebClient, check the corresponding Jira issue. This will be available in Spring Data Elasticsearch 3.2.4 and is already in the current master branch.

Configuration code looks like this:

@Configuration
public class ReactiveRestClientConfig extends AbstractReactiveElasticsearchConfiguration {
    @Override
    public ReactiveElasticsearchClient reactiveElasticsearchClient() {
        final ClientConfiguration clientConfiguration = ClientConfiguration.builder() //
                .connectedTo("localhost:9200") //
                .withWebClientConfigurer(webClient -> {
                    ExchangeStrategies exchangeStrategies = ExchangeStrategies.builder()
                            .codecs(configurer -> configurer.defaultCodecs()
                                    .maxInMemorySize(-1))
                            .build();
                    return webClient.mutate().exchangeStrategies(exchangeStrategies).build();
                })
                .build();
        return ReactiveRestClients.create(clientConfiguration);

    }
}