Jason White created SPARK-11437:
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Summary: createDataFrame shouldn't .take() when provided schema
Key: SPARK-11437
URL: https://issues.apache.org/jira/browse/SPARK-11437
Project: Spark
Issue Type: Improvement
Components: PySpark
Reporter: Jason White
When creating a DataFrame from an RDD in PySpark, `createDataFrame` calls
`.take(10)` to verify the first 10 rows of the RDD match the provided schema.
Similar to https://issues.apache.org/jira/browse/SPARK-8070, but that issue
affected cases where a schema was not provided.
Verifying the first 10 rows is of limited utility and causes the DAG to be
executed non-lazily. If necessary, I believe this verification should be done
lazily on all rows. However, since the caller is providing a schema to follow,
I think it's acceptable to simply fail if the schema is incorrect.
https://github.com/apache/spark/blob/master/python/pyspark/sql/context.py#L321-L325
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