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  1. Nutch
  2. NUTCH-2474

CrawlDbReader -stats fails with ClassCastException

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Details

    • Bug
    • Status: Resolved
    • Critical
    • Resolution: Fixed
    • 1.14
    • 1.14
    • crawldb
    • None
    • Java 8, distributed mode: Hadoop CDH 5.13.0

    Description

      In distributed mode CrawlDbReader / readdb -stats fails with a ClassCastException in the combiner:

      17/12/08 04:57:13 INFO mapreduce.Job: Task Id : attempt_1512553291624_0022_m_000039_0, Status : FAILED
      Error: java.lang.ClassCastException: org.apache.hadoop.io.FloatWritable cannot be cast to org.apache.hadoop.io.LongWritable
              at org.apache.nutch.crawl.CrawlDbReader$CrawlDbStatCombiner.reduce(CrawlDbReader.java:296)
              at org.apache.nutch.crawl.CrawlDbReader$CrawlDbStatCombiner.reduce(CrawlDbReader.java:222)
              at org.apache.hadoop.mapred.Task$OldCombinerRunner.combine(Task.java:1639)
              at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.mergeParts(MapTask.java:1946)
              at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.flush(MapTask.java:1514)
              at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:466)
              at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
      

      FloatWritables are used since NUTCH-2470, so that's when this bug was introduced.

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              snagel Sebastian Nagel
              snagel Sebastian Nagel
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                Updated:
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