Examples with SQLPullDataset io.cdap.cdap.etl.api.engine.sql.dataset.SQLPullDataset used on opensource projects

Example 1 with SQLPullDataset

use of io.cdap.cdap.etl.api.engine.sql.dataset.SQLPullDataset in project cdap by caskdata.

the class BatchSQLEngineAdapter method pullInternal.

/**
 * Pull implementation. This method has blocking calls and should be executed in a separate thread.
 *
 * @param dataset the dataset to pull.
 * @return {@link JavaRDD} representing the records contained in this dataset.
 * @throws SQLEngineException if the pull process fails.
 */
@SuppressWarnings("unchecked,raw")
private <T> JavaRDD<T> pullInternal(SQLDataset dataset) throws SQLEngineException {
    // Create pull operation for this dataset and wait until completion
    SQLPullRequest pullRequest = new SQLPullRequest(dataset);
    // If so, we will process this request using a producer.
    for (PullCapability capability : sqlEngine.getPullCapabilities()) {
        SQLDatasetProducer producer = sqlEngine.getProducer(pullRequest, capability);
        // If a producer is able to produce records for this pull request, extract the RDD from this request.
        if (producer != null) {
            RecordCollection recordCollection = producer.produce(dataset);
            // If the collection that got generarted is not an instance of a SparkRecordCollection, skip.
            if (recordCollection instanceof SparkRecordCollection) {
                Schema schema = dataset.getSchema();
                return (JavaRDD<T>) ((SparkRecordCollection) recordCollection).getDataFrame().javaRDD().map(r -> DataFrames.fromRow((Row) r, schema));
            }
        }
    }
    // If no capabilities could be used to produce records, proceed using the Pull Provider.
    SQLPullDataset<StructuredRecord, ?, ?> sqlPullDataset = sqlEngine.getPullProvider(pullRequest);
    // Run operation to read from the InputFormatProvider supplied by this operation.
    ClassLoader classLoader = Objects.firstNonNull(Thread.currentThread().getContextClassLoader(), getClass().getClassLoader());
    JavaPairRDD pairRDD = RDDUtils.readUsingInputFormat(jsc, sqlPullDataset, classLoader, Object.class, Object.class);
    return pairRDD.flatMap(new TransformFromPairFunction(sqlPullDataset.fromKeyValue()));
}