问题描述：

在Spark中使用elasticsearch的RestClient API在读取es中数据时，出现TimeoutException，在之前的优化的中做下面的超时设置，这个只能解决request retries exceeded max retry timeout [30000]这种超时：

RestClient build = RestClient.builder(httpHosts).setMaxRetryTimeoutMillis(5*60*1000).build();

java.lang.RuntimeException: error while performing request
        at org.elasticsearch.client.RestClient$SyncResponseListener.get(RestClient.java:681)
        at org.elasticsearch.client.RestClient.performRequest(RestClient.java:219)
        at org.elasticsearch.client.RestClient.performRequest(RestClient.java:191)
        at org.elasticsearch.client.RestHighLevelClient.performRequest(RestHighLevelClient.java:396)
        at org.elasticsearch.client.RestHighLevelClient.performRequestAndParseEntity(RestHighLevelClient.java:382)
        at org.elasticsearch.client.RestHighLevelClient.search(RestHighLevelClient.java:323)
        at com.bbd.finance.commons.utils.ESSparkUtils.readBySingleField(ESSparkUtils.java:410)
        at com.bbd.finance.fc.functions.stream.StreamFuncUtils.lambda$null$4(StreamFuncUtils.java:366)
        at java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1626)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.util.concurrent.TimeoutException
        at org.apache.http.nio.pool.AbstractNIOConnPool.processPendingRequest(AbstractNIOConnPool.java:364)
        at org.apache.http.nio.pool.AbstractNIOConnPool.processNextPendingRequest(AbstractNIOConnPool.java:344)
        at org.apache.http.nio.pool.AbstractNIOConnPool.release(AbstractNIOConnPool.java:318)
        at org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager.releaseConnection(PoolingNHttpClientConnectionManager.java:364)
        at org.apache.http.impl.nio.client.AbstractClientExchangeHandler.releaseConnection(AbstractClientExchangeHandler.java:245)
        at org.apache.http.impl.nio.client.MainClientExec.responseCompleted(MainClientExec.java:387)
        at org.apache.http.impl.nio.client.DefaultClientExchangeHandlerImpl.responseCompleted(DefaultClientExchangeHandlerImpl.java:172)
        at org.apache.http.nio.protocol.HttpAsyncRequestExecutor.processResponse(HttpAsyncRequestExecutor.java:436)
        at org.apache.http.nio.protocol.HttpAsyncRequestExecutor.inputReady(HttpAsyncRequestExecutor.java:326)
        at org.apache.http.impl.nio.client.InternalRequestExecutor.inputReady(InternalRequestExecutor.java:83)
        at org.apache.http.impl.nio.DefaultNHttpClientConnection.consumeInput(DefaultNHttpClientConnection.java:265)
        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:588)
        ... 1 more

public static final int DEFAULT_CONNECT_TIMEOUT_MILLIS = 1000;
public static final int DEFAULT_SOCKET_TIMEOUT_MILLIS = 30000;
public static final int DEFAULT_MAX_RETRY_TIMEOUT_MILLIS = DEFAULT_SOCKET_TIMEOUT_MILLIS;
public static final int DEFAULT_CONNECTION_REQUEST_TIMEOUT_MILLIS = 500;

所以我们将之前的初始化RestClient的代码做了如下的修改：

RestClientBuilder builder = RestClient.builder(httpHosts).setRequestConfigCallback(new RestClientBuilder.RequestConfigCallback() {
            @Override
            public RequestConfig.Builder customizeRequestConfig(RequestConfig.Builder requestConfigBuilder) {
                requestConfigBuilder.setConnectTimeout(5000);
                requestConfigBuilder.setSocketTimeout(40000);
                requestConfigBuilder.setConnectionRequestTimeout(1000);
                return requestConfigBuilder;
            }
        }).setMaxRetryTimeoutMillis(5*60*1000);

        RestHighLevelClient client = new RestHighLevelClient(builder.build());