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Nicholas Chammas edited comment on SPARK-15193 at 5/10/16 4:27 PM: ------------------------------------------------------------------- Nope, a sampling ratio of 1.0 and None mean [different things|http://spark.apache.org/docs/1.6.1/api/python/pyspark.sql.html#pyspark.sql.SQLContext.createDataFrame]: {quote} If schema inference is needed, samplingRatio is used to determined the ratio of rows used for schema inference. The first row will be used if samplingRatio is None. {quote} createDataFrame() is not consistent with jsonRDD() as of 1.6.1. Looking in master, I can't seem to find jsonRDD() for Python anymore, so perhaps that got removed. So actually you're right, it looks like the default _did_ get standardized, but to None. :/ was (Author: nchammas): Nope, a sampling ratio of 1.0 and None mean [different things|http://spark.apache.org/docs/1.6.1/api/python/pyspark.sql.html#pyspark.sql.SQLContext.createDataFrame]: {quote} If schema inference is needed, samplingRatio is used to determined the ratio of rows used for schema inference. The first row will be used if samplingRatio is None. {quote} createDataFrame() is not consistent with jsonRDD() as of 1.6.1. Looking in master, I can't seem to find jsonRDD() for Python anymore, so perhaps that got removed. So actually, it looks like the default _did_ get standardized, but to None. :/ > samplingRatio should default to 1.0 across the board > ---------------------------------------------------- > > Key: SPARK-15193 > URL: https://issues.apache.org/jira/browse/SPARK-15193 > Project: Spark > Issue Type: Improvement > Components: PySpark, SQL > Reporter: Nicholas Chammas > Priority: Minor > > The default sampling ratio for {{jsonRDD}} is > [1.0|http://spark.apache.org/docs/1.6.1/api/python/pyspark.sql.html#pyspark.sql.SQLContext.jsonRDD], > whereas for {{createDataFrame}} it's > [{{None}}|http://spark.apache.org/docs/1.6.1/api/python/pyspark.sql.html#pyspark.sql.SQLContext.createDataFrame]. > I think the default sampling ratio should be 1.0 across the board. Users > should have to explicitly supply a lower sampling ratio if they know their > dataset has a consistent structure. Otherwise, I think the "safer" thing to > default to is to check all the data. > Targeting this for 2.0 in case we consider it a breaking change that would be > more difficult to get in later. -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org