Re: Reading parquet files in parallel on the cluster

Why not just read from Spark as normal? Do these files have different or incompatible schemas? val df = spark.read.option(“mergeSchema”, “true”).load(listOfPaths) From: Eric Beabes Date: Tuesday, May 25, 2021 at 1:24 PM To: spark-user Subject: Reading parquet files in parallel on the cluster

Re: Poor performance caused by coalesce to 1

As I suggested, you need to use repartition(1) in place of coalesce(1) That will give you a single file output without losing parallelization for the rest of the job. From: James Yu Date: Wednesday, February 3, 2021 at 2:19 PM To: Silvio Fiorito , user Subject: Re: Poor performance caused by

Re: Poor performance caused by coalesce to 1

Coalesce is reducing the parallelization of your last stage, in your case to 1 task. So, it’s natural it will give poor performance especially with large data. If you absolutely need a single file output, you can instead add a stage boundary and use repartition(1). This will give your query full

Re: pandas_udf is very slow

Your 2 examples are doing different things. The Pandas UDF is doing a grouped map, whereas your Python UDF is doing an aggregate. I think you want your Pandas UDF to be PandasUDFType.GROUPED_AGG? Is your result the same? From: Lian Jiang Date: Sunday, April 5, 2020 at 3:28 AM To: user Subjec

Re: Parquet 'bucketBy' creates a ton of files

-from-the-field-episode-ii-applying-best-practices-to-your-apache-spark-applications-with-silvio-fiorito From: Gourav Sengupta Date: Wednesday, July 10, 2019 at 3:14 AM To: Silvio Fiorito Cc: Arwin Tio , "user@spark.apache.org" Subject: Re: Parquet 'bucketBy' creates a ton

Re: Parquet 'bucketBy' creates a ton of files

You need to first repartition (at a minimum by bucketColumn1) since each task will write out the buckets/files. If the bucket keys are distributed randomly across the RDD partitions, then you will get multiple files per bucket. From: Arwin Tio Date: Thursday, July 4, 2019 at 3:22 AM To: "user@s

Re: [pyspark 2.3+] Bucketing with sort - incremental data load?

Spark does allow appending new files to bucketed tables. When the data is read in, Spark will combine the multiple files belonging to the same buckets into the same partitions. Having said that, you need to be very careful with bucketing especially as you’re appending to avoid generating lots o

Re: [Spark SQL] Does Spark group small files

Yes, it does bin-packing for small files which is a good thing so you avoid having many small partitions especially if you’re writing this data back out (e.g. it’s compacting as you read). The default partition size is 128MB with a 4MB “cost” for opening files. You can configure this using the s

Re: performance of IN clause

Have you run explain for each query? If you look at the physical query plan it’s most likely the same. If the inner-query/join-table is small enough it should end up as a broadcast join. From: Jayesh Lalwani Date: Wednesday, October 17, 2018 at 5:03 PM To: "user@spark.apache.org" Subject: perf

Re: [Structured Streaming] Avoiding multiple streaming queries

-foreachbatch) Nothing’s free! 😉 Since you’re just pushing all messages to kafka, might be easier on you to just explode the rows and let Spark do the rest for you. From: kant kodali Date: Tuesday, July 24, 2018 at 1:04 PM To: Silvio Fiorito Cc: Arun Mahadevan , chandan prakash , Tathagata Das

Re: [Structured Streaming] Avoiding multiple streaming queries

Using the current Kafka sink that supports routing based on topic column, you could just duplicate the rows (e.g. explode rows with different topic, key values). That way you’re only reading and processing the source once and not having to resort to custom sinks, foreachWriter, or multiple queri

Re: Bulk / Fast Read and Write with MSSQL Server and Spark

Try this https://docs.microsoft.com/en-us/azure/sql-database/sql-database-spark-connector From: Chetan Khatri Date: Wednesday, May 23, 2018 at 7:47 AM To: user Subject: Bulk / Fast Read and Write with MSSQL Server and Spark All, I am looking for approach to do bulk read / write with MSSQL Se

Re: Custom metrics sink

Just set your custom sink in the org.apache.spark.metrics.sink namespace and configure metrics.properties. Use ConsoleSink as an example. Obviously since it’s private the API may change, but in the meantime that should work… https://github.com/apache/spark/blob/master/core/src/main/scala/org/apa

Re: Writing a DataFrame is taking too long and huge space

Given you start with ~250MB but end up with 58GB seems like you’re generating quite a bit of data. Whether you use coalesce or repartition, still writing out 58GB with one core is going to take a while. Using Spark to do pre-processing but output a single file is not going to be very efficient

Re: How to properly execute `foreachPartition` in Spark 2.2

Couldn’t you readStream from Kafka, do your transformations, map your rows from the transformed input into what you want need to send to Kafka, then writeStream to Kafka? From: Liana Napalkova Date: Monday, December 18, 2017 at 10:07 AM To: Silvio Fiorito , "user@spark.apache.org"

Re: How to properly execute `foreachPartition` in Spark 2.2

Why don’t you just use the Kafka sink for Spark 2.2? https://spark.apache.org/docs/2.2.0/structured-streaming-kafka-integration.html#creating-a-kafka-sink-for-streaming-queries From: Liana Napalkova Date: Monday, December 18, 2017 at 9:45 AM To: "user@spark.apache.org" Subject: How to properl

Re: How to...UNION ALL of two SELECTs over different data sources in parallel?

Hi Jacek, Just replied to the SO thread as well, but… Yes, your first statement is correct. The DFs in the union are read in the same stage, so in your example where each DF has 8 partitions then you have a stage with 16 tasks to read the 2 DFs. There's no need to define the DF in a separate t

Re: Generating StructType from dataframe.printSchema

If you’re confident the schema of all files is consistent, then just infer the schema from a single file and reuse it when loading the whole data set: val schema = spark.read.json(“/path/to/single/file.json”).schema val wholeDataSet = spark.read.schema(schema).json(“/path/to/whole/datasets”) T

Re: best spark spatial lib?

There’s a number of packages for geospatial analysis, depends on the features you need. Here are a few I know of and/or have used: Magellan: https://github.com/harsha2010/magellan MrGeo: https://github.com/ngageoint/mrgeo GeoMesa: http://www.geomesa.org/documentation/tutorials/spark.html GeoSpark

Re: [StructuredStreaming] multiple queries of the socket source: only one query works.

Hi Gerard, Each query has its own distinct query plan and tracks offsets independently from other queries. Also, each query will generate a dynamic group id to ensure it gets all events and appears as a new consumer from Kafka’s perspective, that’s done internally to the Kafka source. That’s wh

Re: Does spark 2.1.0 structured streaming support jdbc sink?

JDBC sink is not in 2.1. You can see here for an example implementation using the ForEachWriter sink instead: https://databricks.com/blog/2017/04/04/real-time-end-to-end-integration-with-apache-kafka-in-apache-sparks-structured-streaming.html From: Hemanth Gudela Date: Sunday, April 9, 2017 at

Re: TDD in Spark

You should check out Holden’s excellent spark-testing-base package: https://github.com/holdenk/spark-testing-base From: A Shaikh Date: Sunday, January 15, 2017 at 1:14 PM To: User Subject: TDD in Spark Whats the most popular Testing approach for Spark App. I am looking something in the line

Re: How to connect Tableau to databricks spark?

Also, meant to add the link to the docs: https://docs.databricks.com/user-guide/faq/tableau.html From: Silvio Fiorito Date: Monday, January 9, 2017 at 2:59 PM To: Raymond Xie , user Subject: Re: How to connect Tableau to databricks spark? Hi Raymond, Are you using a Spark 2.0 or 1.6 cluster

Re: How to connect Tableau to databricks spark?

Hi Raymond, Are you using a Spark 2.0 or 1.6 cluster? With Spark 2.0 it’s just a matter of entering the hostname of your Databricks environment, the HTTP path from the cluster page, and your Databricks credentials. Thanks, Silvio From: Raymond Xie Date: Sunday, January 8, 2017 at 10:30 PM To:

Re: Cluster deploy mode driver location

Hi Saif! Unfortunately, I don't think this is possible for YARN driver-cluster mode. Regarding the JARs you're referring to, can you place them on HDFS so you can then have them in a central location and refer to them that way for dependencies? http://spark.apache.org/docs/latest/submitting-

Re: Joining to a large, pre-sorted file

Hi Stuart, Yes that's the query plan but if you take a look at my screenshot it skips the first stage since the datasets are co-partitioned. Thanks, Silvio From: Stuart White Sent: Saturday, November 12, 2016 11:20:28 AM To: Silvio Fiorito Cc:

Re: Joining to a large, pre-sorted file

Hi Stuart, You don’t need the sortBy or sortWithinPartitions. https://databricks-prod-cloudfront.cloud.databricks.com/public/4027ec902e239c93eaaa8714f173bcfc/594325853373464/879901972425732/6861830365114179/latest.html This is what the job should look like: [cid:image001.png@01D23CD0.

Re: Joining to a large, pre-sorted file

You want to look at the bucketBy option when you save the master file out. That way it will be pre-partitioned by the join column, eliminating the shuffle on the larger file. From: Stuart White Date: Thursday, November 10, 2016 at 8:39 PM To: Jörn Franke Cc: "user@spark.apache.org" Subject:

Re: Physical plan for windows and joins - how to know which is faster?

Hi Jacek, I haven't played with 2.1.0 yet, so not sure how much more optimized Window functions are compared to 1.6 and 2.0. However, one thing I do see in the self-join is a broadcast. So there's going to be a need broadcast the results of the groupBy out to the executors before it can do t

Re: How do I convert a data frame to broadcast variable?

Hi Nishit, Yes the JDBC connector supports predicate pushdown and column pruning. So any selection you make on the dataframe will get materialized in the query sent via JDBC. You should be able to verify this by looking at the physical query plan: val df = sqlContext.jdbc().select($"col

Re: DataFrame defined within conditional IF ELSE statement

Oh, sorry it was supposed to be sys.error, not sys.err From: Mich Talebzadeh Date: Sunday, September 18, 2016 at 5:23 PM To: Silvio Fiorito Cc: "user @spark" Subject: Re: DataFrame defined within conditional IF ELSE statement Thanks Silvio. This is what I ended up with val d

Re: DataFrame defined within conditional IF ELSE statement

Hi Mich, That’s because df2 is only within scope in the if statements. Try this: val df = option match { case 1 => { println("option = 1") val df = spark.read.option("header", false).csv("hdfs://rhes564:9000/data/prices/prices.*") val df2 = df.map(p => columns(p(0).toString.toInt,

Re: what contribute to Task Deserialization Time

Are you referencing member variables or other objects of your driver in your transformations? Those would have to be serialized and shipped to each executor when that job kicks off. On 7/22/16, 8:54 AM, "Jacek Laskowski" wrote: Hi, I can't specifically answer your question, but my understandi

Re: Deploying ML Pipeline Model

Hi Rishabh, My colleague, Richard Garris from Databricks, actually just gave a talk last night at the Bay Area Spark Meetup on ML model deployment. The slides and recording should be up soon, you should be able to find a link here: http://www.meetup.com/spark-users/events/231574440/ Thanks, Si

Re: Strategies for propery load-balanced partitioning

Hi Saif! When you say this happens with spark-csv, are the files gzipped by any chance? GZip is non-splittable so if you’re seeing skew simply from loading data it could be you have some extremely large gzip files. So for a single stage job you will have those tasks lagging compared to the smal

Re: HiveContext standalone => without a Hive metastore

Hi Gerard, I’ve never had an issue using the HiveContext without a hive-site.xml configured. However, one issue you may have is if multiple users are starting the HiveContext from the same path, they’ll all be trying to store the default Derby metastore in the same location. Also, if you want t

Re: Using HiveContext.set in multipul threads

If you’re using DataFrame API you can achieve that by simply using (or not) the “partitionBy” method on the DataFrameWriter: val originalDf = …. val df1 = originalDf…. val df2 = originalDf… df1.write.partitionBy(”col1”).save(…) df2.write.save(…) From: Amir Gershman Date: Tuesday, May 24, 201

Re: "collecting" DStream data

Hi Daniel, Given your example, “arr” is defined on the driver, but the “foreachRDD” function is run on the executors. If you want to collect the results of the RDD/DStream down to the driver you need to call RDD.collect. You have to be careful though that you have enough memory on the driver JV

RE: Apache Flink

Actually there were multiple responses to it on the GitHub project, including a PR to improve the Spark code, but they weren’t acknowledged. From: Ovidiu-Cristian MARCU Sent: Sunday, April 17, 2016 7:48 AM To: andy petrella C

Re: How to configure parquet.block.size on Spark 1.6

Have you tried: sc.hadoopConfiguration.setLong(parquet.hadoop.ParquetOutputFormat.BLOCK_SIZE, N * 1024 * 1024) Not sure if it’d work or not, but since it’s getting it from the Hadoop config it should do it. From: nihed mbarek mailto:nihe...@gmail.com>> Date: Friday, April 8, 2016 at 12:01 PM

RE: Spark Metrics : Why is the Sink class declared private[spark] ?

In the meantime you can simply define your custom metric source in the org.apache.spark package. From: Walid Lezzar Sent: Saturday, April 2, 2016 4:23 AM To: Saisai Shao Cc: spark users Subject: Re: Spark Met

Re: Spark Metrics Framework?

system. I would suggest going ahead and submitting a JIRA request if there isn’t one already. Thanks, Silvio From: Mike Sukmanowsky mailto:mike.sukmanow...@gmail.com>> Date: Friday, March 25, 2016 at 10:48 AM To: Silvio Fiorito mailto:silvio.fior...@granturing.com>>, "user@spark

Re: Spark Metrics Framework?

Hi Mike, It’s been a while since I worked on a custom Source but I think all you need to do is make your Source in the org.apache.spark package. Thanks, Silvio From: Mike Sukmanowsky mailto:mike.sukmanow...@gmail.com>> Date: Tuesday, March 22, 2016 at 3:13 PM To: Silvio F

Re: Work out date column in CSV more than 6 months old (datediff or something)

There’s a months_between function you could use, as well: df.filter(months_between(current_date, $”Payment Date”) > 6).show From: Mich Talebzadeh mailto:mich.talebza...@gmail.com>> Date: Monday, March 21, 2016 at 5:53 PM To: "user @spark" mailto:user@spark.apache.org>> Subject: Work out date col

Re: Spark Metrics Framework?

You could use the metric sources and sinks described here: http://spark.apache.org/docs/latest/monitoring.html#metrics If you want to push the metrics to another system you can define a custom sink. You can also extend the metrics by defining a custom source. From: Mike Sukmanowsky mailto:mike

Re: Get the number of days dynamically in with Column

I’m not entirely sure if this is what you’re asking, but you could just use the datediff function: val df2 = df.withColumn("ID”, datediff($"end", $"start”)) If you want it formatted as {n}D then: val df2 = df.withColumn("ID", concat(datediff($"end", $"start"),lit("D"))) Thanks, Silvio From: D

RE: Extra libs in executor classpath

Could you publish it as a library (to an internal repo) then you can simply use the “--packages" option? Also will help with versioning as you make changes, that way you’re not having to manually ship JARs around to your machines and users. From: Леонид Поляков Sent:

RE: Spark on YARN memory consumption

Hi Jan, Yes what you’re seeing is due to YARN container memory overhead. Also, typically the memory increments for YARN containers is 1GB. This gives a good overview: http://blog.cloudera.com/blog/2015/03/how-to-tune-your-apache-spark-jobs-part-2/ Thanks, Silvio From: Jan Štěrba<

RE: Achieving 700 Spark SQL Queries Per Second

Very cool stuff Evan. Thanks for your work on this and sharing! From: Evan Chan Sent: Thursday, March 10, 2016 1:38 PM To: user@spark.apache.org Subject: Achieving 700 Spark SQL Queries Per Second Hey folks, I just saw a recen

RE: Using dynamic allocation and shuffle service in Standalone Mode

There’s a script to start it up under sbin, start-shuffle-service.sh. Run that on each of your worker nodes. From: Yuval Itzchakov<mailto:yuva...@gmail.com> Sent: Tuesday, March 8, 2016 2:17 PM To: Silvio Fiorito<mailto:silvio.fior...@granturing.com>; user@spark.apache.org

RE: Using dynamic allocation and shuffle service in Standalone Mode

You’ve started the external shuffle service on all worker nodes, correct? Can you confirm they’re still running and haven’t exited? From: Yuval.Itzchakov Sent: Tuesday, March 8, 2016 12:41 PM To: user@spark.apache.org Subject: Using dy

RE: Stage contains task of large size

One source of this could be more than you intended (or realized) getting serialized as part of your operations. What are the transformations you’re using? Are you referencing local instance variables in your driver app, as part of your transformations? You may have a large collection for insta

Re: Unit testing framework for Spark Jobs?

Please check out the following for some good resources: https://github.com/holdenk/spark-testing-base https://spark-summit.org/east-2016/events/beyond-collect-and-parallelize-for-tests/ On 3/2/16, 12:54 PM, "SRK" wrote: >Hi, > >What is a good unit testing framework for Spark batch/streami

Re: Save DataFrame to Hive Table

Just do: val df = sqlContext.read.load(“/path/to/parquets/*”) If you do df.explain it’ll show the multiple input paths. From: "andres.fernan...@wellsfargo.com" mailto:andres.fernan...@wellsfargo.com>> Date: Tuesday, March 1, 2016 at 12:00 PM To: "user@spa

Re: Union Parquet, DataFrame

Just replied to your other email, but here’s the same thing: Just do: val df = sqlContext.read.load(“/path/to/parquets/*”) If you do df.explain it’ll show the multiple input paths. From: "andres.fernan...@wellsfargo.com" mailto:andres.fernan...@wellsfarg

RE: Use maxmind geoip lib to process ip on Spark/Spark Streaming

I’ve used the code below with SparkSQL. I was using this with Spark 1.4 but should still be good with 1.6. In this case I have a UDF to do the lookup, but for Streaming you’d just have a lambda to apply in a map function, so no UDF wrapper. import org.apache.spark.sql.functions._ import java.i

Re: map operation clears custom partitioner

You can use mapValues to ensure partitioning is not lost. From: Brian London mailto:brianmlon...@gmail.com>> Date: Monday, February 22, 2016 at 1:21 PM To: user mailto:user@spark.apache.org>> Subject: map operation clears custom partitioner It appears that when a custom partitioner is applied in

RE: coalesce and executor memory

pher Brady<mailto:christopher.br...@oracle.com> Sent: Friday, February 12, 2016 8:34 PM To: Koert Kuipers<mailto:ko...@tresata.com>; Silvio Fiorito<mailto:silvio.fior...@granturing.com> Cc: user<mailto:user@spark.apache.org> Subject: Re: coalesce and executor memory Thank you for the respon

Re: coalesce and executor memory

Coalesce essentially reduces parallelism, so fewer cores are getting more records. Be aware that it could also lead to loss of data locality, depending on how far you reduce. Depending on what you’re doing in the map operation, it could lead to OOM errors. Can you give more details as to what th

Re: Allowing parallelism in spark local mode

You’ll want to setup the FAIR scheduler as described here: https://spark.apache.org/docs/latest/job-scheduling.html#scheduling-within-an-application From: yael aharon mailto:yael.aharo...@gmail.com>> Date: Friday, February 12, 2016 at 2:00 PM To: "user@spark.apache.org

Re: Spark with .NET

That’s just a .NET assembly (not related to Spark DataSets) but doesn’t look like they’re actually using it. It’s typically a default reference pulled in by the project templates. The code though is available from Mono here: https://github.com/mono/mono/tree/master/mcs/class/System.Data.DataSet

Re: Unit test with sqlContext

Hi Steve, Have you looked at the spark-testing-base package by Holden? It’s really useful for unit testing Spark apps as it handles all the bootstrapping for you. https://github.com/holdenk/spark-testing-base DataFrame examples are here: https://github.com/holdenk/spark-testing-base/blob/maste

Re: General Question (Spark Hive integration )

Also, just to clarify it doesn’t read the whole table into memory unless you specifically cache it. From: Silvio Fiorito mailto:silvio.fior...@granturing.com>> Date: Thursday, January 21, 2016 at 10:02 PM To: "Balaraju.Kagidala Kagidala" mailto:balaraju.kagid...@gma

Re: General Question (Spark Hive integration )

Hi Bala, It depends on how your Hive table is configured. If you used partitioning and you are filtering on a partition column then it will only load the relevant partitions. If, however, you’re filtering on a non-partitioned column then it will have to read all the data and then filter as part

Re: visualize data from spark streaming

You’ve got a few options: * Use a notebook tool such as Zeppelin, Jupyter, or Spark Notebook to write up some visualizations which update in time with your streaming batches * Use Spark Streaming to push your batch results to another 3rd-party system with a BI tool that supports realtime

Re: Spark Streaming: BatchDuration and Processing time

It will just queue up the subsequent batches, however if this delay is constant you may start losing batches. It can handle spikes in processing time, but if you know you're consistently running over your batch duration you either need to increase the duration or look at enabling back pressure s

Re: why one of Stage is into Skipped section instead of Completed

Skipped stages result from existing shuffle output of a stage when re-running a transformation. The executors will have the output of the stage in their local dirs and Spark recognizes that, so rather than re-computing, it will start from the following stage. So, this is a good thing in that you

Re: Spark data frame

Michael, collect will bring down the results to the driver JVM, whereas the RDD or DataFrame would be cached on the executors (if it is cached). So, as Dean said, the driver JVM needs to have enough memory to store the results of collect. Thanks, Silvio From: Michael Segel mailto:msegel_had..

Re: Testing with spark testing base

Yes, with IntelliJ you can set up a scalatest run configuration. You can also run directly from the sbt CLI by running “sbt test” From: Masf mailto:masfwo...@gmail.com>> Date: Saturday, December 5, 2015 at 12:51 PM To: "user@spark.apache.org" mailto:user@spark.apac

Re: key not found: sportingpulse.com in Spark SQL 1.5.0

I don’t believe I have it on 1.5.1. Are you able to test the data locally to confirm, or is it too large? From: "Zhang, Jingyu" mailto:jingyu.zh...@news.com.au>> Date: Friday, October 30, 2015 at 7:31 PM To: Silvio Fiorito mailto:silvio.fior...@granturing.com>> Cc

RE: key not found: sportingpulse.com in Spark SQL 1.5.0

It's something due to the columnar compression. I've seen similar intermittent issues when caching DataFrames. "sportingpulse.com" is a value in one of the columns of the DF. From: Ted Yu Sent: ‎10/‎30/‎2015 6:33 PM To: Zhang, Jingyu

Re: how to merge two dataframes

Are you able to upgrade to Spark 1.5.1 and Cassandra connector to latest version? It no longer requires a separate CassandraSQLContext. From: Yana Kadiyska mailto:yana.kadiy...@gmail.com>> Reply-To: "yana.kadiy...@gmail.com" mailto:yana.kadiy...@gmail.com>> Date:

Re: Maintaining overall cumulative data in Spark Streaming

In the update function you can return None for a key and it will remove it. If you’re restarting your app you can delete your checkpoint directory to start from scratch, rather than continuing from the previous state. From: Sandeep Giri mailto:sand...@knowbigdata.com>> Date: Friday, October 30,

RE: Maintaining overall cumulative data in Spark Streaming

You could use updateStateByKey. There's a stateful word count example on Github. https://github.com/apache/spark/blob/master/examples/src/main/scala/org/apache/spark/examples/streaming/StatefulNetworkWordCount.scala From: Sandeep Giri

RE: Concurrent execution of actions within a driver

There is a collectAsync action if you want to run them in parallel, but keep in mind the two jobs will need to share resources and you should use the FAIR scheduler. From: praveen S Sent: ‎10/‎26/‎2015 4:27 AM To: user@spark.apache.org<

RE: Dynamic Resource Allocation with Spark Streaming (Standalone Cluster, Spark 1.5.1)

Hi Matthias, Unless there was a change in 1.5, I'm afraid dynamic resource allocation is not yet supported in streaming apps. Thanks, Silvio Sent from my Lumia 930 From: Matthias Niehoff Sent: ‎10/‎26/‎2015 4:00 PM To: use

Re: Java REST custom receiver

When you say “receive messages” you mean acting as a REST endpoint, right? If so, it might be better to use JMS (or Kafka) option for a few reasons: The receiver will be deployed to any of the available executors, so your REST clients will need to be made aware of the IP where the receiver is ru

Re: Receiver and Parallelization

One thing you should look at is your batch duration and spark.streaming.blockInterval Those 2 things control how many partitions are generated for each RDD (batch) of the DStream when using a receiver (vs direct approach). So if you have a 2 second batch duration and the default blockInterval o

Re: DataFrame repartition not repartitioning

You just need to assign it to a new variable: val avroFile = sqlContext.read.format("com.databricks.spark.avro").load(inFile) val repart = avroFile.repartition(10) repart.save(outFile, "parquet") From: Steve Annessa Date: Wednesday, September 16, 2015 at 2:08 PM To: "user@spark.apache.org

Re: Where can I learn how to write udf?

Hi Saif, There are 2 types of UDFs. Those used by SQL and those used by the Scala DSL. For SQL, you just register a function like so (this example is from the docs): sqlContext.udf.register(“strLen”, (s: String) => s.length) sqlContext.sql(“select name, strLen(name) from people”).show The othe

Re: Realtime Data Visualization Tool for Spark

So if you want to build your own from the ground up, then yes you could go the d3js route. Like Feynman also responded you could use something like Spark Notebook or Zeppelin to create some charts as well. It really depends on your intended audience and ultimate goal. If you just want some count

Re: Can Spark Provide Multiple Context Support?

Is the data from HDFS static or is it unique for each event in the stream? If it’s static, you can just create the SparkContext, load the files from HDFS, then start a StreamingContext with the existing SparkContext and go from there. From: Rachana Srivastava Date: Tuesday, September 8, 2015 at

Re: Unbale to run Group BY on Large File

Unfortunately, groupBy is not the most efficient operation. What is it you’re trying to do? It may be possible with one of the other *byKey transformations. From: "SAHA, DEBOBROTA" Date: Wednesday, September 2, 2015 at 7:46 PM To: "'user@spark.apache.org'" Subject: Unbale to run Group BY on Large

Re: Help! Stuck using withColumn

Hi Saif, In both cases you’re referencing columns that don’t exist in the current DataFrame. The first email you did a select and then a withColumn for ‘month_date_cur' on the resulting DF, but that column does not exist, because you did a select for only ‘month_balance’. In the second email

Re: Left outer joining big data set with small lookups

table2.value.registerTempTable(“table2”) > >Broadcast is also having same issue as explained above. All data processed by >just executors due to lookup skew. > >Any more idea to tackle this issue in Spark Dataframe? > >Thanks >Vijay > > >> On Aug 14, 2015, at 10:27 AM,

Re: Left outer joining big data set with small lookups

You could cache the lookup DataFrames, it’ll then do a broadcast join. On 8/14/15, 9:39 AM, "VIJAYAKUMAR JAWAHARLAL" wrote: >Hi > >I am facing huge performance problem when I am trying to left outer join very >big data set (~140GB) with bunch of small lookups [Start schema type]. I am >usin

Re: Spark DataFrames uses too many partition

You need to configure the spark.sql.shuffle.partitions parameter to a different value. It defaults to 200. On 8/11/15, 11:31 AM, "Al M" wrote: >I am using DataFrames with Spark 1.4.1. I really like DataFrames but the >partitioning makes no sense to me. > >I am loading lots of very small fil

RE: How to increase parallelism of a Spark cluster?

Can you share the transformations up to the foreachPartition? From: Sujit Pal Sent: ‎8/‎2/‎2015 4:42 PM To: Igor Berman Cc: user Subject: Re: How to increase parallelism of a

Re: Executing spark code in Zeppelin

Hi Stefan, Might be best to move this over to the Zeppelin user list at us...@zeppelin.incubator.apache.org For now, do you see any errors in the logs? Could be a syntax or compiler error that isn’t getting reported back to the UI. Thanks, Silvio From: Stefan Panayotov Date: Wednesday, July 2

Re: Local Repartition

Hi Daniel, Coalesce, by default will not cause a shuffle. The second parameter when set to true will cause a full shuffle. This is actually what repartition does (calls coalesce with shuffle=true). It will attempt to keep colocated partitions together (as you describe) on the same executor. Wh

Re: Sessionization using updateStateByKey

Hi Cody, I’ve had success using updateStateByKey for real-time sessionization by aging off timed-out sessions (returning None in the update function). This was on a large commercial website with millions of hits per day. This was over a year ago so I don’t have access to the stats any longer fo

Re: .NET on Apache Spark?

Joe Duffy, director of engineering on Microsoft's compiler team made a comment about investigating F# type providers for Spark. https://twitter.com/xjoeduffyx/status/614076012372955136 From: Ashic Mahtab Sent: ?Sunday?, ?July? ?5?, ?2015 ?1?:?29? ?PM To: Ruslan Dautkhano

Re: Optimizations

One thing you could do is a broadcast join. You take your smaller RDD, save it as a broadcast variable. Then run a map operation to perform the join and whatever else you need to do. This will remove a shuffle stage but you will still have to collect the joined RDD and broadcast it. All depends

Re: Spark Streaming broadcast to all keys

updateStateByKey will run for all keys, whether they have new data in a batch or not so you should be able to still use it. On 7/3/15, 7:34 AM, "micvog" wrote: >UpdateStateByKey is useful but what if I want to perform an operation to all >existing keys (not only the ones in this RDD). > >Word

Re: Spark performance issue

It’ll help to see the code or at least understand what transformations you’re using. Also, you have 15 nodes but not using all of them, so that means you may be losing data locality. You can see this in the job UI for Spark if any jobs do not have node or process local. From: diplomatic Guru D

Re: map vs foreach for sending data to external system

foreach absolutely runs on the executors. For sending data to an external system you should likely use foreachPartition in order to batch the output. Also if you want to limit the parallelism of the output action then you can use coalesce. What makes you think foreach is running on the driver?

RE: .NET on Apache Spark?

Since Spark runs on the JVM, no there isn't support for .Net. You should take a look at Dryad and Naiad instead. https://github.com/MicrosoftResearch/ From: Zwits Sent: ‎7/‎2/‎2015 4:33 AM To: user@spark.apache.org

Re: custom RDD in java

Sure, you can create custom RDDs. Haven’t done so in Java, but in Scala absolutely. From: Shushant Arora Date: Wednesday, July 1, 2015 at 1:44 PM To: Silvio Fiorito Cc: user Subject: Re: custom RDD in java ok..will evaluate these options but is it possible to create RDD in java? On Wed, Jul 1

Re: custom RDD in java

If all you’re doing is just dumping tables from SQLServer to HDFS, have you looked at Sqoop? Otherwise, if you need to run this in Spark could you just use the existing JdbcRDD? From: Shushant Arora Date: Wednesday, July 1, 2015 at 10:19 AM To: user Subject: custom RDD in java Hi Is it possi

Re: Shuffle files lifecycle

Regarding 1 and 2, yes shuffle output is stored on the worker local disks and will be reused across jobs as long as they’re available. You can identify when they’re used by seeing skipped stages in the job UI. They are periodically cleaned up based on available space of the configured spark.loca

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