I don’t know how to interpolate in PySpark when the DataFrame contains many columns. Let me xplain.
from pyspark.sql.functions import to_timestamp df = spark.createDataFrame([ ("John", "A", "2018-02-01 03:00:00", 60), ("John", "A", "2018-02-01 03:03:00", 66), ("John", "A", "2018-02-01 03:05:00", 70), ("John", "A", "2018-02-01 03:08:00", 76), ("Mo", "A", "2017-06-04 01:05:00", 10), ("Mo", "A", "2017-06-04 01:07:00", 20), ("Mo", "B", "2017-06-04 01:10:00", 35), ("Mo", "B", "2017-06-04 01:11:00", 40), ], ("webID", "aType", "timestamp", "counts")).withColumn( "timestamp", to_timestamp("timestamp") )
I need to group by webID
and interpolate counts
values at 1 minute interval. However, when I apply the below-shown code,
from operator import attrgetter from pyspark.sql.types import StructType from pyspark.sql.functions import pandas_udf, PandasUDFType def resample(schema, freq, timestamp_col = "timestamp",**kwargs): @pandas_udf( StructType(sorted(schema, key=attrgetter("name"))), PandasUDFType.GROUPED_MAP) def _(pdf): pdf.set_index(timestamp_col, inplace=True) pdf = pdf.resample(freq).interpolate() pdf.ffill(inplace=True) pdf.reset_index(drop=False, inplace=True) pdf.sort_index(axis=1, inplace=True) return pdf return _ df.groupBy("webID").apply(resample(df.schema, "60S")).show()
Error:
py4j.protocol.Py4JJavaError: An error occurred while calling o371.showString. : org.apache.spark.SparkException: Job aborted due to stage failure: Task 77 in stage 31.0 failed 4 times, most recent failure: Lost task 77.3 in stage 31.0 (TID 812, 27faa516aadb4c40b7d7586d7493143c0021c825663, executor 2): java.lang.IllegalArgumentException at java.nio.ByteBuffer.allocate(ByteBuffer.java:334)
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Answer
Set the environment variable ARROW_PRE_0_15_IPC_FORMAT=1
.
def resample(schema, freq, timestamp_col = "timestamp",**kwargs): @pandas_udf( StructType(sorted(schema, key=attrgetter("name"))), PandasUDFType.GROUPED_MAP) def _(pdf): import os # add this line os.environ['ARROW_PRE_0_15_IPC_FORMAT']='1' # add this line pdf.set_index(timestamp_col, inplace=True) pdf = pdf.resample(freq).interpolate() pdf.ffill(inplace=True) pdf.reset_index(drop=False, inplace=True) pdf.sort_index(axis=1, inplace=True) return pdf return _