ES查询报错：entity content is too long [142501157] for the configured buffer limit [104857600]

在生产环境批量同步数据的时候，我写了一个查询请求，然后直接报错：entity content is too long [142501157] for the configured buffer limit [104857600]

具体内容如下：

Caused by: org.apache.http.ContentTooLongException: entity content is too long [142501157] for the configured buffer limit [104857600]
        at org.elasticsearch.client.HeapBufferedAsyncResponseConsumer.onEntityEnclosed(HeapBufferedAsyncResponseConsumer.java:76)
        at org.apache.http.nio.protocol.AbstractAsyncResponseConsumer.responseReceived(AbstractAsyncResponseConsumer.java:137)
        at org.apache.http.impl.nio.client.MainClientExec.responseReceived(MainClientExec.java:315)
        at org.apache.http.impl.nio.client.DefaultClientExchangeHandlerImpl.responseReceived(DefaultClientExchangeHandlerImpl.java:151)
        at org.apache.http.nio.protocol.HttpAsyncRequestExecutor.responseReceived(HttpAsyncRequestExecutor.java:315)
        at org.apache.http.impl.nio.DefaultNHttpClientConnection.consumeInput(DefaultNHttpClientConnection.java:255)
        at org.apache.http.impl.nio.client.InternalIODispatch.onInputReady(InternalIODispatch.java:81)
        at org.apache.http.impl.nio.client.InternalIODispatch.onInputReady(InternalIODispatch.java:39)
        at org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:114)
        at org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:162)
        at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:337)
        at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:315)
        at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:276)
        at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104)
        at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:591)
        at java.lang.Thread.run(Thread.java:748)
        Suppressed: org.apache.http.ContentTooLongException: entity content is too long [142501157] for the configured buffer limit [104857600]
                ... 16 more
                Suppressed: org.apache.http.ContentTooLongException: entity content is too long [142501157] for the configured buffer limit [104857600]
                        ... 16 more

在HttpAsyncResponseConsumerFactory类中：

在HeapBufferedAsyncResponseConsumer类中有一个判断：返回的内容长度大于限定的100MB就会抛出ContentTooLongException异常。

我这里用的依赖是：

            <dependency>
                <groupId>org.elasticsearch.client</groupId>
                <artifactId>elasticsearch-rest-client</artifactId>
                <version>6.6.2</version>
            </dependency>

            <dependency>
                <groupId>org.elasticsearch.client</groupId>
                <artifactId>transport</artifactId>
                <version>6.6.2</version>
            </dependency>

            <dependency>
                <groupId>org.elasticsearch.client</groupId>
                <artifactId>elasticsearch-rest-high-level-client</artifactId>
                <version>6.6.2</version>
            </dependency>

            <dependency>
                <groupId>org.elasticsearch</groupId>
                <artifactId>elasticsearch</artifactId>
                <version>6.6.2</version>
            </dependency>

而我们对es进行查询操作，或者其他增删改操作是，都会默认使用如下的RequestOptions.DEFAULT

进入RequestOptions.DEFAULT看它的代码：这里用了HeapBufferedResponseConsumerFactory.DEFAULT

而这个HeapBufferedResponseConsumerFactory.DEFAULT,就是我们之前看到的，已经被限制了100MB返回值的HeapBufferedResponseConsumerFactory。

所以有两种方式可以解决这个bug。

方式一：

不使用默认的RequestOptions.DEFAULT，而通过使用自定义RequestOptions的方式（ES官方api已经给我们开放出来了）：

RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
builder.setHttpAsyncResponseConsumerFactory(
    new HttpAsyncResponseConsumerFactory
    //修改为500MB
    .HeapBufferedResponseConsumerFactory(500 * 1024 * 1024));

方式二：

如果不方便修改怎么办，例如我们使用的是Spring Data ElasticSearch或者是其他的一些框架，而它默认使用的也是RequestOptions.DEFAULT

这时候我们可以通过java反射进行修改：

        //设置es查询buffer大小
        RequestOptions requestOptions = RequestOptions.DEFAULT;
        Class<? extends RequestOptions> reqClass = requestOptions.getClass();
        Field reqField = reqClass.getDeclaredField("httpAsyncResponseConsumerFactory");
        reqField.setAccessible(true);
        //去除final
        Field modifiersField = Field.class.getDeclaredField("modifiers");
        modifiersField.setAccessible(true);
        modifiersField.setInt(reqField, reqField.getModifiers() & ~Modifier.FINAL);

        //设置默认的工厂
        reqField.set(requestOptions, new HttpAsyncResponseConsumerFactory() {
            @Override
            public HttpAsyncResponseConsumer<HttpResponse> createHttpAsyncResponseConsumer() {
                //500MB
                return new HeapBufferedAsyncResponseConsumer(5 * 100 * 1024 * 1024);
            }
        });

如果你使用的是springmvc，那么可以把这段代码加入到拦截器中，这样可以拦截需要自定义返回值大小的es请求