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  1. Apache Drill
  2. DRILL-4977

Reading parquet metadata cache from S3 with fadvise=random and Hadoop 3 generates a large number of requests

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Details

    • Improvement
    • Status: Open
    • Major
    • Resolution: Unresolved
    • 1.8.0
    • None
    • Storage - Parquet
    • None

    • Hadoop 3.0

    Description

      When using the new fs.s3a.experimental.input.fadvise=random mode for accessing Parquet files stored in S3, we see a significant improvement for the query performance but a slowdown on query planning. This is due to the way the metadata file is read (each chunk of 8000 bytes generates a new GET request to S3). Indicating with FSDataInputStream.setReadahead(metadata-filesize) that we will read the whole file, this behaviour is circumvented.

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          relates to

          Improvement - An improvement or enhancement to an existing feature or task. DRILL-6540 Upgrade to HADOOP-3.0 libraries

          • Major - Major loss of function.
          • Closed

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              Unassigned Unassigned
              uwe Uwe Korn
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              Dates

                Created:
                Updated: