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Data Engineering
Join discussions on data engineering best practices, architectures, and optimization strategies within the Databricks Community. Exchange insights and solutions with fellow data engineers.
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Forum Posts

paourissi
by New Contributor
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When to persist and when to unpersist RDD in Spark

Lets say i have the following:<code>val dataset2 = dataset1.persist(StorageLevel.MEMORY_AND_DISK) val dataset3 = dataset2.map(.....)1) 1)If you do a transformation on the dataset2 then you have to persist it and pass it to dataset3 and unpersist ...

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Arun_KumarPT
New Contributor II
  • 1 kudos

It is well documented here : http://spark.apache.org/docs/latest/programming-guide.html#rdd-persistence

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z160896
by New Contributor II
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why spark very slow with large number of dataframe columns

scala Spark App: I have a dataset of 130x14000. I read from a parquet file with SparkSession. Then used for Spark ML Random Forest model (using pipeline). It takes 7 hours to complete! for reading the parquet file takes about 1 minute. If I implemen...

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EliasHaydar
New Contributor II
  • 0 kudos

I've already answered a similar question on StackOverflow so I'll repeat what a I said there. The following may not solve your problem completely but it should give you some pointer to start. The first problem that you are facing is the disproportio...

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XinZodl
by New Contributor III
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Resolved! How to parse a file with newline character, escaped with \ and not quoted

Hi! I am facing an issue when reading and parsing a CSV file. Some records have a newline symbol, "escaped" by a \, and that record not being quoted. The file might look like this: Line1field1;Line1field2.1 \ Line1field2.2;Line1field3; Line2FIeld1;...

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XinZodl
New Contributor III
  • 1 kudos

Solution is "sparkContext.wholeTextFiles"

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Mallesh
by New Contributor
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  • 1 replies
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How can i read parquet file compressed by snappy?

Hi All, I wanted to read parqet file compressed by snappy into Spark RDD input file name is: part-m-00000.snappy.parquet i have used sqlContext.setConf("spark.sql.parquet.compression.codec.", "snappy") val inputRDD=sqlContext.parqetFile(args(0)) whe...

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raela
New Contributor III
  • 0 kudos

Have you tried sqlContext.read.parquet("/filePath/") ?

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