Examples with HiveSubScan org.apache.drill.exec.store.hive.HiveSubScan used on opensource projects

Example 1 with HiveSubScan

use of org.apache.drill.exec.store.hive.HiveSubScan in project drill by apache.

the class ReadersInitializer method init.

/**
 * Selects reader constructor reference as {@link HiveReaderFactory} readerFactory.
 * Then check if input splits are empty creates empty record reader, or one reader per split otherwise.
 *
 * @param ctx    context related to fragment
 * @param config context which holds different Hive configurations
 * @return list containing one or more readers
 */
public static List<RecordReader> init(ExecutorFragmentContext ctx, HiveSubScan config) {
    final HiveReaderFactory readerFactory = getReaderFactory(config);
    final UserGroupInformation proxyUgi = ImpersonationUtil.createProxyUgi(config.getUserName(), ctx.getQueryUserName());
    final List<List<InputSplit>> inputSplits = config.getInputSplits();
    final HiveConf hiveConf = config.getHiveConf();
    if (inputSplits.isEmpty()) {
        return Collections.singletonList(readerFactory.createReader(config.getTable(), null, /*partition*/
        null, /*split*/
        config.getColumns(), ctx, hiveConf, proxyUgi));
    } else {
        IndexedPartitions partitions = getPartitions(config);
        return IntStream.range(0, inputSplits.size()).mapToObj(idx -> readerFactory.createReader(config.getTable(), partitions.get(idx), inputSplits.get(idx), config.getColumns(), ctx, hiveConf, proxyUgi)).collect(Collectors.toList());
    }
}