[jira] [Created] (HIVE-22891) Skip PartitonDesc Extraction In CombineHiveRecord For Non-LLAP Execution Mode

["Syed Shameerur Rahman (Jira)" <ji...@apache.org>]

Syed Shameerur Rahman created HIVE-22891:
--------------------------------------------

             Summary: Skip PartitonDesc Extraction In CombineHiveRecord For Non-LLAP Execution Mode
                 Key: HIVE-22891
                 URL: https://issues.apache.org/jira/browse/HIVE-22891
             Project: Hive
          Issue Type: Task
            Reporter: Syed Shameerur Rahman
            Assignee: Syed Shameerur Rahman
             Fix For: 4.0.0


{code:java}
try {
      // TODO: refactor this out
      if (pathToPartInfo == null) {
        MapWork mrwork;
        if (HiveConf.getVar(conf, HiveConf.ConfVars.HIVE_EXECUTION_ENGINE).equals("tez")) {
          mrwork = (MapWork) Utilities.getMergeWork(jobConf);
          if (mrwork == null) {
            mrwork = Utilities.getMapWork(jobConf);
          }
        } else {
          mrwork = Utilities.getMapWork(jobConf);
        }
        pathToPartInfo = mrwork.getPathToPartitionInfo();
      }      PartitionDesc part = extractSinglePartSpec(hsplit);
      inputFormat = HiveInputFormat.wrapForLlap(inputFormat, jobConf, part);
    } catch (HiveException e) {
      throw new IOException(e);
    }
{code}
The above piece of code in CombineHiveRecordReader.java was introduced in HIVE-15147. This overwrites inputFormat based on the PartitionDesc which is not required in non-LLAP mode of execution as the method HiveInputFormat.wrapForLlap() simply returns the previously defined inputFormat in case of non-LLAP mode. The method call extractSinglePartSpec() has some serious performance implications. If there are large no. of small files, each call in the method extractSinglePartSpec() takes approx ~ (2 - 3) seconds. Hence the same query which runs in Hive 1.x / Hive 2 is way faster than the query run on latest hive.
{code:java}
2020-02-11 07:15:04,701 INFO [main] org.apache.hadoop.hive.ql.io.orc.ReaderImpl: Reading ORC rows from  <S3://>2020-02-11 

07:15:06,468 WARN [main] org.apache.hadoop.hive.ql.io.CombineHiveRecordReader: Multiple partitions found; not going to pass a part spec to LLAP IO: {{logdate=2020-02-03, hour=01, event=win}} and {{logdate=2020-02-03, hour=02, event=act}}

2020-02-11 07:15:06,468 INFO [main] org.apache.hadoop.hive.ql.io.CombineHiveRecordReader: succeeded in getting org.apache.hadoop.mapred.FileSplit{code}



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