Spark and Cassandra 2 Fast 2 Furious
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Spark and Cassandra with the Datastax Spark Cassandra Connector How it works and how to use it! Missed Spark Summit but Still want to see some slides? This slide deck is for you!
](https://image.slidesharecdn.com/ss2016-toofasttoofurious-160608235227/85/Spark-and-Cassandra-2-Fast-2-Furious-44-320.jpg)
.select("vehicle_id").where("ts > 10")
SELECT "vehicle_id" FROM TABLE
WHERE
Token(PK) > 500 AND
Token(PK) < 600 AND
ts > 10](https://image.slidesharecdn.com/ss2016-toofasttoofurious-160608235227/85/Spark-and-Cassandra-2-Fast-2-Furious-45-320.jpg)
.select("name" as "_1", "zipcode" as "_2", "userid")
.keyBy[Tuple1[Int]]("userid")
}
rdd.partitioner
//res3: Option[org.apache.spark.Partitioner] =
Some(com.datastax.spark.connector.rdd.partitioner.CassandraPartitioner@94515d3e)](https://image.slidesharecdn.com/ss2016-toofasttoofurious-160608235227/85/Spark-and-Cassandra-2-Fast-2-Furious-57-320.jpg)
.select("purchaseid" as "_1", "amount" as "_2", "objectid" as "_3", "userid")
.keyBy[Tuple1[Int]]("userid")
}
val rdd2 = { sc.cassandraTable[(String, Int)](ks, "users")
.select("name" as "_1", "zipcode" as "_2", "userid")
.keyBy[Tuple1[Int]]("userid")
}.applyPartitionerFrom(rdd1) // Assigns the partitioner from the first rdd to this one
val joinRDD = rdd1.join(rdd2)](https://image.slidesharecdn.com/ss2016-toofasttoofurious-160608235227/85/Spark-and-Cassandra-2-Fast-2-Furious-58-320.jpg)
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Spark and Cassandra 2 Fast 2 Furious
- 1. Spark and Cassandra: 2 Fast, 2 Furious Russell Spitzer DataStax Inc.
- 2. Russell, ostensibly a software engineer • Did a Ph.D in bioinformatics at some point • Written a great deal of automation and testing framework code • Now develops for Datastax on the Analytics Team • Focuses a lot on the Datastax OSS Spark Cassandra Connector
- 3. Datastax Spark Cassandra Connector Let Spark Interact with your Cassandra Data! https://github.com/datastax/spark-cassandra-connector http://spark-packages.org/package/datastax/spark-cassandra-connector http://spark-packages.org/package/TargetHolding/pyspark-cassandra Compatible with Spark 1.6 + Cassandra 3.0 • Bulk writing to Cassandra • Distributed full table scans • Optimized direct joins with Cassandra • Secondary index pushdown • Connection and prepared statement pools
- 4. Cassandra is essentially a hybrid between a key-value and a column-oriented (or tabular) database management system. Its data model is a partitioned row store with tunable consistency* *https://en.wikipedia.org/wiki/Apache_Cassandra Let's break that down 1.What is a C* Partition and Row 2.How does C* Place Partitions
- 5. CQL looks a lot like SQL CREATE TABLE tracker ( vehicle_id uuid, ts timestamp, x double, y double, PRIMARY KEY (vehicle_id, ts))
- 6. INSERTS look almost Identical CREATE TABLE tracker ( vehicle_id uuid, ts timestamp, x double, y double, PRIMARY KEY (vehicle_id, ts)) INSERT INTO tracker (vehicle_id, ts, x, y) Values ( 1, 0, 0, 1)
- 7. Cassandra Data is stored in Partitions CREATE TABLE tracker ( vehicle_id uuid, ts timestamp, x double, y double, PRIMARY KEY (vehicle_id, ts)) vehicle_id 1 ts: 0 x: 0 y: 1 INSERT INTO tracker (vehicle_id, ts, x, y) Values ( 1, 0, 0, 1)
- 8. C* Partitions Store Many Rows CREATE TABLE tracker ( vehicle_id uuid, ts timestamp, x double, y double, PRIMARY KEY (vehicle_id, ts)) vehicle_id 1 ts: 0 x: 0 y: 1 ts: 1 x: -1 y:0 ts: 2 x: 0 y: -1 ts: 3 x: 1 y: 0
- 9. C* Partitions Store Many Rows CREATE TABLE tracker ( vehicle_id uuid, ts timestamp, x double, y double, PRIMARY KEY (vehicle_id, ts)) vehicle_id 1 ts: 0 x: 0 y: 1 ts: 1 x: -1 y:0 ts: 2 x: 0 y: -1 ts: 3 x: 1 y: 0Partition
- 10. C* Partitions Store Many Rows CREATE TABLE tracker ( vehicle_id uuid, ts timestamp, x double, y double, PRIMARY KEY (vehicle_id, ts)) vehicle_id 1 ts: 0 x: 0 y: 1 ts: 1 x: -1 y:0 ts: 2 x: 0 y: -1 ts: 3 x: 1 y: 0Row
- 11. Within a partition there is ordering based on the Clustering Keys CREATE TABLE tracker ( vehicle_id uuid, ts timestamp, x double, y double, PRIMARY KEY (vehicle_id, ts)) vehicle_id 1 ts: 0 x: 0 y: 1 ts: 1 x: -1 y:0 ts: 2 x: 0 y: -1 ts: 3 x: 1 y: 0 Ordered by Clustering Key
- 12. Slices within a Partition are Very Easy CREATE TABLE tracker ( vehicle_id uuid, ts timestamp, x double, y double, PRIMARY KEY (vehicle_id, ts)) vehicle_id 1 ts: 0 x: 0 y: 1 ts: 1 x: -1 y:0 ts: 2 x: 0 y: -1 ts: 3 x: 1 y: 0 Ordered by Clustering Key
- 13. Cassandra is a Distributed Fault-Tolerant Database San Jose Oakland San Francisco
- 14. Data is located on a Token Range San Jose Oakland San Francisco
- 15. Data is located on a Token Range 0 San Jose Oakland San Francisco 1200 600
- 16. The Partition Key of a Row is Hashed to Determine it's Token 0 San Jose Oakland San Francisco 1200 600
- 17. The Partition Key of a Row is Hashed to Determine it's Token 01200 600 San Jose Oakland San Francisco vehicle_id 1 INSERT INTO tracker (vehicle_id, ts, x, y) Values ( 1, 0, 0, 1)
- 18. The Partition Key of a Row is Hashed to Determine it's Token 01200 600 San Jose Oakland San Francisco vehicle_id 1 INSERT INTO tracker (vehicle_id, ts, x, y) Values ( 1, 0, 0, 1) Hash(1) = 1000
- 19. How The Spark Cassandra Connector Reads 0 500
- 20. How The Spark Cassandra Connector Reads 0 San Jose Oakland San Francisco 500
- 21. Spark Partitions are Built From the Token Range 0 San Jose Oakland San Francisco 500 500 - 600 600 - 700 500 1200
- 22. Each Partition Can be Drawn Locally from at Least One Node 0 San Jose Oakland San Francisco 500 500 - 600 600 - 700 500 1200
- 23. Each Partition Can be Drawn Locally from at Least One Node 0 San Jose Oakland San Francisco 500 500 - 600 600 - 700 500 1200 Spark Executor Spark Executor Spark Executor
- 24. No Need to Leave the Node For Data! 0 500
- 25. Data is Retrieved using the Datastax Java Driver 0 Spark Executor Cassandra
- 26. A Connection is Established 0 Spark Executor Cassandra 500 - 600
- 27. A Query is Prepared with Token Bounds 0 Spark Executor Cassandra SELECT * FROM TABLE WHERE Token(PK) > StartToken AND Token(PK) < EndToken500 - 600
- 28. The Spark Partitions Bounds are Placed in the Query 0 Spark Executor Cassandra SELECT * FROM TABLE WHERE Token(PK) > 500 AND Token(PK) < 600500 - 600
- 29. Paged a number of rows at a Time 0 Spark Executor Cassandra 500 - 600 SELECT * FROM TABLE WHERE Token(PK) > 500 AND Token(PK) < 600
- 30. Data is Paged 0 Spark Executor Cassandra 500 - 600 SELECT * FROM TABLE WHERE Token(PK) > 500 AND Token(PK) < 600
- 31. Data is Paged 0 Spark Executor Cassandra 500 - 600 SELECT * FROM TABLE WHERE Token(PK) > 500 AND Token(PK) < 600
- 32. Data is Paged 0 Spark Executor Cassandra 500 - 600 SELECT * FROM TABLE WHERE Token(PK) > 500 AND Token(PK) < 600
- 33. Data is Paged 0 Spark Executor Cassandra 500 - 600 SELECT * FROM TABLE WHERE Token(PK) > 500 AND Token(PK) < 600
- 34. How we write to Cassandra • Data is written via the Datastax Java Driver • Data is grouped based on Partition Key (configurable) • Batches are written
- 35. Data is Written using the Datastax Java Driver 0 Spark Executor Cassandra
- 36. A Connection is Established 0 Spark Executor Cassandra
- 37. Data is Grouped on Key 0 Spark Executor Cassandra
- 38. Data is Grouped on Key 0 Spark Executor Cassandra
- 39. Once a Batch is Full or There are Too Many Batches The Largest Batch is Executed 0 Spark Executor Cassandra
- 40. Once a Batch is Full or There are Too Many Batches The Largest Batch is Executed 0 Spark Executor Cassandra
- 41. Once a Batch is Full or There are Too Many Batches The Largest Batch is Executed 0 Spark Executor Cassandra
- 42. Once a Batch is Full or There are Too Many Batches The Largest Batch is Executed 0 Spark Executor Cassandra
- 43. Most Common Features • RDD APIs • cassandraTable • saveToCassandra • repartitionByCassandraTable • joinWithCassandraTable • DF API • Datasource
- 44. Full Table Scans, Making an RDD out of a Table import com.datastax.spark.connector._ sc.cassandraTable(KeyspaceName, TableName) import com.datastax.spark.connector._ sc.cassandraTable[MyClass](KeyspaceName, TableName)
- 45. Pushing Down CQL to Cassandra import com.datastax.spark.connector._ sc.cassandraTable[MyClass](KeyspaceName, TableName).select("vehicle_id").where("ts > 10") SELECT "vehicle_id" FROM TABLE WHERE Token(PK) > 500 AND Token(PK) < 600 AND ts > 10
- 46. Distributed Key Retrieval import com.datastax.spark.connector._ rdd.joinWithCassandraTable("keyspace", "table") San Jose Oakland San Francisco Spark Executor Spark Executor Spark Executor RDD
- 47. But our Data isn't Colocated import com.datastax.spark.connector._ rdd.joinWithCassandraTable("keyspace", "table") San Jose Oakland San Francisco Spark Executor Spark Executor Spark Executor RDD
- 48. RBCR Moves bulk reshuffles our data so Data Will Be Local rdd .repartitionByCassandraReplica("keyspace","table") .joinWithCassandraTable("keyspace", "table") San Jose Oakland San Francisco Spark Executor Spark Executor Spark Executor RDD
- 49. The Connector Provides a Distributed Pool for Prepared Statements and Sessions CassandraConnector(sc.getConf) rdd.mapPartitions{ it => { val ps = CassandraConnector(sc.getConf) .withSessionDo( s => s.prepare) it.map{ ps.bind(_).executeAsync()} } Your Pool Ready to Be Deployed
- 50. The Connector Provides a Distributed Pool for Prepared Statements and Sessions CassandraConnector(sc.getConf) rdd.mapPartitions{ it => { val ps = CassandraConnector(sc.getConf) .withSessionDo( s => s.prepare) it.map{ ps.bind(_).executeAsync()} } Your Pool Ready to Be Deployed Prepared Statement Cache Session Cache
- 51. The Connector Supports the DataSources Api sqlContext .read .format("org.apache.spark.sql.cassandra") .options(Map("keyspace" -> "read_test", "table" -> "simple_kv")) .load import org.apache.spark.sql.cassandra._ sqlContext .read .cassandraFormat("read_test","table") .load https://github.com/datastax/spark-cassandra-connector/blob/master/doc/14_data_frames.md
- 52. The Connector Works with Catalyst to Pushdown Predicates to Cassandra import com.datastax.spark.connector._ df.select("vehicle_id").filter("ts > 10") SELECT "vehicle_id" FROM TABLE WHERE Token(PK) > 500 AND Token(PK) < 600 AND ts > 10
- 53. The Connector Works with Catalyst to Pushdown Predicates to Cassandra import com.datastax.spark.connector._ df.select("vehicle_id").filter("ts > 10") QueryPlan Catalyst PrunedFilteredScan Only Prunes (projections) and Filters (predicates) are able to be pushed down.
- 54. Recent Features • C* 3.0 Support • Materialized Views • SASL Indexes (for pushdown) • Advanced Spark Partitioner Support • Increased Performance on JWCT
- 55. Use C* Partitioning in Spark
- 56. Use C* Partitioning in Spark • C* Data is Partitioned • Spark has Partitions and partitioners • Spark can use a known partitioner to speed up Cogroups (joins) • How Can we Leverage this?
- 57. Use C* Partitioning in Spark https://github.com/datastax/spark-cassandra-connector/blob/master/doc/16_partitioning.md Now if keyBy is used on a CassandraTableScanRDD and the PartitionKey is included in the key. The RDD will be given a C* Partitioner val ks = "doc_example" val rdd = { sc.cassandraTable[(String, Int)](ks, "users") .select("name" as "_1", "zipcode" as "_2", "userid") .keyBy[Tuple1[Int]]("userid") } rdd.partitioner //res3: Option[org.apache.spark.Partitioner] = Some(com.datastax.spark.connector.rdd.partitioner.CassandraPartitioner@94515d3e)
- 58. Use C* Partitioning in Spark https://github.com/datastax/spark-cassandra-connector/blob/master/doc/16_partitioning.md Share partitioners between Tables for joins on Partition Key val ks = "doc_example" val rdd1 = { sc.cassandraTable[(Int, Int, String)](ks, "purchases") .select("purchaseid" as "_1", "amount" as "_2", "objectid" as "_3", "userid") .keyBy[Tuple1[Int]]("userid") } val rdd2 = { sc.cassandraTable[(String, Int)](ks, "users") .select("name" as "_1", "zipcode" as "_2", "userid") .keyBy[Tuple1[Int]]("userid") }.applyPartitionerFrom(rdd1) // Assigns the partitioner from the first rdd to this one val joinRDD = rdd1.join(rdd2)
- 59. Use C* Partitioning in Spark https://github.com/datastax/spark-cassandra-connector/blob/master/doc/16_partitioning.md Many other uses for this, try it yourself! • All self joins using the Partition key • Groups within C* Partitions • Anything formerly using SpanBy • Joins with other RDDs And much more!
- 60. Enhanced Parallelism with JWCT • joinWithCassandraTable now has increased concurrency and parallelism! • 5X Speed increases in some cases • https://datastax-oss.atlassian.net/browse/ SPARKC-233 • Thanks Jaroslaw!
- 61. The Connector wants you! • OSS Project that loves community involvement • Bug Reports • Feature Requests • Doc Improvements • Come join us! Vin Diesel may or may not be a contributor
- 62. Tons of Videos at Datastax Academy https://academy.datastax.com/ https://academy.datastax.com/courses/getting-started-apache-spark
- 63. Tons of Videos at Datastax Academy https://academy.datastax.com/ https://academy.datastax.com/courses/getting-started-apache-spark
- 64. See you at Cassandra Summit! Join me and 3500 of your database peers, and take a deep dive into Apache Cassandra™, the massively scalable NoSQL database that powers global businesses like Apple, Spotify, Netflix and Sony. San Jose Convention Center September 7-9, 2016 https://cassandrasummit.org/ Build Something Disruptive