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StartQueryExample.java

StartQueryExample.java demonstrates how to submit a query to Athena for execution, wait till results are available, and then process the results.

/* * Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"). * You may not use this file except in compliance with the License. * A copy of the License is located at * * http://aws.amazon.com/apache2.0 * * or in the "license" file accompanying this file. This file is distributed * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either * express or implied. See the License for the specific language governing * permissions and limitations under the License. */ package aws.example.athena; import software.amazon.awssdk.services.athena.AthenaClient; import software.amazon.awssdk.services.athena.model.*; import software.amazon.awssdk.services.athena.paginators.GetQueryResultsIterable; import java.util.List; /** * StartQueryExample * ------------------------------------- * This code shows how to submit a query to Athena for execution, wait till results * are available, and then process the results. */ public class StartQueryExample { public static void main(String[] args) throws InterruptedException { // Build an AthenaClient client AthenaClientFactory factory = new AthenaClientFactory(); AthenaClient athenaClient = factory.createClient(); String queryExecutionId = submitAthenaQuery(athenaClient); waitForQueryToComplete(athenaClient, queryExecutionId); processResultRows(athenaClient, queryExecutionId); } /** * Submits a sample query to Athena and returns the execution ID of the query. */ private static String submitAthenaQuery(AthenaClient athenaClient) { // The QueryExecutionContext allows us to set the Database. QueryExecutionContext queryExecutionContext = QueryExecutionContext.builder() .database(ExampleConstants.ATHENA_DEFAULT_DATABASE).build(); // The result configuration specifies where the results of the query should go in S3 and encryption options ResultConfiguration resultConfiguration = ResultConfiguration.builder() // You can provide encryption options for the output that is written. // .withEncryptionConfiguration(encryptionConfiguration) .outputLocation(ExampleConstants.ATHENA_OUTPUT_BUCKET).build(); // Create the StartQueryExecutionRequest to send to Athena which will start the query. StartQueryExecutionRequest startQueryExecutionRequest = StartQueryExecutionRequest.builder() .queryString(ExampleConstants.ATHENA_SAMPLE_QUERY) .queryExecutionContext(queryExecutionContext) .resultConfiguration(resultConfiguration).build(); StartQueryExecutionResponse startQueryExecutionResponse = athenaClient.startQueryExecution(startQueryExecutionRequest); return startQueryExecutionResponse.queryExecutionId(); } /** * Wait for an Athena query to complete, fail or to be cancelled. This is done by polling Athena over an * interval of time. If a query fails or is cancelled, then it will throw an exception. */ private static void waitForQueryToComplete(AthenaClient athenaClient, String queryExecutionId) throws InterruptedException { GetQueryExecutionRequest getQueryExecutionRequest = GetQueryExecutionRequest.builder() .queryExecutionId(queryExecutionId).build(); GetQueryExecutionResponse getQueryExecutionResponse; boolean isQueryStillRunning = true; while (isQueryStillRunning) { getQueryExecutionResponse = athenaClient.getQueryExecution(getQueryExecutionRequest); String queryState = getQueryExecutionResponse.queryExecution().status().state().toString(); if (queryState.equals(QueryExecutionState.FAILED.toString())) { throw new RuntimeException("Query Failed to run with Error Message: " + getQueryExecutionResponse .queryExecution().status().stateChangeReason()); } else if (queryState.equals(QueryExecutionState.CANCELLED.toString())) { throw new RuntimeException("Query was cancelled."); } else if (queryState.equals(QueryExecutionState.SUCCEEDED.toString())) { isQueryStillRunning = false; } else { // Sleep an amount of time before retrying again. Thread.sleep(ExampleConstants.SLEEP_AMOUNT_IN_MS); } System.out.println("Current Status is: " + queryState); } } /** * This code calls Athena and retrieves the results of a query. * The query must be in a completed state before the results can be retrieved and * paginated. The first row of results are the column headers. */ private static void processResultRows(AthenaClient athenaClient, String queryExecutionId) { GetQueryResultsRequest getQueryResultsRequest = GetQueryResultsRequest.builder() // Max Results can be set but if its not set, // it will choose the maximum page size // As of the writing of this code, the maximum value is 1000 // .withMaxResults(1000) .queryExecutionId(queryExecutionId).build(); GetQueryResultsIterable getQueryResultsResults = athenaClient.getQueryResultsPaginator(getQueryResultsRequest); for (GetQueryResultsResponse Resultresult : getQueryResultsResults) { List<ColumnInfo> columnInfoList = Resultresult.resultSet().resultSetMetadata().columnInfo(); List<Row> results = Resultresult.resultSet().rows(); processRow(results, columnInfoList); } } private static void processRow(List<Row> row, List<ColumnInfo> columnInfoList) { for (ColumnInfo columnInfo : columnInfoList) { switch (columnInfo.type()) { case "varchar": // Convert and Process as String break; case "tinyint": // Convert and Process as tinyint break; case "smallint": // Convert and Process as smallint break; case "integer": // Convert and Process as integer break; case "bigint": // Convert and Process as bigint break; case "double": // Convert and Process as double break; case "boolean": // Convert and Process as boolean break; case "date": // Convert and Process as date break; case "timestamp": // Convert and Process as timestamp break; default: throw new RuntimeException("Unexpected Type is not expected" + columnInfo.type()); } } } }

Sample Details

Service: athena

Last tested: 2019-04-15

Author: jschwarzwalder AWS

Type: full-example

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