title: Schema not merged properly with an AWS Glue crawler
body: <p>I am currently building a datalake where I run AWS  GlueJobs daily to copy data in our database and make them queryable via AWS Athena. Because the schema of the data I fetch changes often, I crawl them regularly with a Glue Crawler. Unfortunately, when I run the crawler two days in a row and the schema changes I get an error about incompatible schemas: </p>
  
  <pre><code>HIVE_CANNOT_OPEN_SPLIT: Error opening Hive split s3://***/raw/itemstore/parquet_flattened/v1/type=articles/year=2019/month=12/day=12/part-00012-13fc8243-cd4e-47b8-8763-56b15ea46e84-c000.snappy.parquet (offset=0, length=32745292): Schema mismatch, metastore schema for row column item__timeline.element has 10 fields but parquet schema has 9 fields
  
  This query ran against the "***" database, unless qualified by the query. Please post the error message on our forum or contact customer support with Query Id: ***
  </code></pre>
  
  <p>Here is the code for our crawler in cloud formation: </p>
  
  <pre><code>  ItemStoreCrawler:
      Type: AWS::Glue::Crawler
      Properties:
        Name: &lt;A STRING&gt;
        DatabaseName: !Ref DatabaseName
        Configuration: "{\"Version\": 1.0, \"CrawlerOutput\": {\"Partitions\": {\"AddOrUpdateBehavior\": \"InheritFromTable\"},\"Tables\":{\"AddOrUpdateBehavior\":\"MergeNewColumns\"}}}"
        Role: !GetAtt CrawlerRole.Arn
        TablePrefix: String 
        Tags:
          Platform: !Ref Platform
          Maintainer: !Ref Maintainer
          ServerType: !Ref ServerType
          ServiceName: !Sub ${ProjectName}
          Environment: !Ref Environment
  
        Targets:
          S3Targets:
            - Path: String
  </code></pre>
  
  <p>My guess is that the schema merging behavior of my crawler is badly set up in the line starting with <code>Configuration</code> but I cannot find a fix. </p>