spark-engineer

name spark-engineer description Use when writing Spark jobs, debugging performance issues, or configuring cluster settings for Apache Spark applications, distributed data processing pipelines, or big data workloads. Invoke to write DataFrame transformations, optimize Spark SQL queries, implement RDD pipelines, tune shuffle operations, configure executor memory, process .parquet files, handle data partitioning, or build structured streaming analytics. license MIT metadata {"author":"https://github.com/Jeffallan","version":"1.1.0","domain":"data-ml","triggers":"Apache Spark, PySpark, Spark SQL, distributed computing, big data, DataFrame API, RDD, Spark Streaming, structured streaming, data partitioning, Spark performance, cluster computing, data processing pipeline","role":"expert","scope":"implementation","output-format":"code","related-skills":"python-pro, sql-pro, devops-engineer"} Spark Engineer Senior Apache Spark engineer specializing in high-performance distributed data processing, optimizing large-scale ETL pipelines, and building production-grade Spark applications. Core Workflow Analyze requirements - Understand data volume, transformations, latency requirements, cluster resources Design pipeline - Choose DataFrame vs RDD, plan partitioning strategy, identify broadcast opportunities Implement - Write Spark code with optimized transformations, appropriate caching, proper error handling Optimize - Analyze Spark UI, tune shuffle partitions, eliminate skew, optimize joins and aggregations Validate - Check Spark UI for shuffle spill before proceeding; verify partition count with df.rdd.getNumPartitions() ; if spill or skew detected, return to step 4; test with production-scale data, monitor resource usage, verify performance targets Reference Guide Load detailed guidance based on context: Topic Reference Load When Spark SQL & DataFrames references/spark-sql-dataframes.md DataFrame API, Spark SQL, schemas, joins, aggregations RDD Operations references/rdd-operations.md Transformations, actions, pair RDDs, custom partitioners Partitioning & Caching references/partitioning-caching.md Data partitioning, persistence levels, broadcast variables Performance Tuning references/performance-tuning.md Configuration, memory tuning, shuffle optimization, skew handling Streaming Patterns references/streaming-patterns.md Structured Streaming, watermarks, stateful operations, sinks Code Examples Quick-Start Mini-Pipeline (PySpark) from pyspark.sql import SparkSession from pyspark.sql import functions as F from pyspark.sql.types import StructType, StructField, StringType, LongType, DoubleType spark = SparkSession.builder \ .appName( "example-pipeline" ) \ .config( "spark.sql.shuffle.partitions" , "400" ) \ .config( "spark.sql.adaptive.enabled" , "true" ) \ .getOrCreate() # Always define explicit schemas in production schema = StructType([ StructField( "user_id" , StringType(), False ), StructField( "event_ts" , LongType(), False ), StructField( "amount" , DoubleType(), True ), ]) df = spark.read.schema(schema).parquet( "s3://bucket/events/" ) result = df \ . filter (F.col( "amount" ).isNotNull()) \ .groupBy( "user_id" ) \ .agg(F. sum ( "amount" ).alias( "total_amount" ), F.count( "*" ).alias( "event_count" )) # Verify partition count before writing print ( f"Partition count: {result.rdd.getNumPartitions()} " ) result.write.mode( "overwrite" ).parquet( "s3://bucket/output/" ) Broadcast Join (small dimension table < 200 MB) from pyspark.sql.functions import broadcast # Spark will automatically broadcast dim_table; hint makes intent explicit enriched = large_fact_df.join(broadcast(dim_df), on= "product_id" , how= "left" ) Handling Data Skew with Salting import pyspark.sql.functions as F SALT_BUCKETS = 50 # Add salt to the skewed key on both sides skewed_df = skewed_df.withColumn( "salt" , (F.rand() * SALT_BUCKETS).cast( "int" )) \ .withColumn( "salted_key" , F.concat(F.col( "skewed_key" ), F.lit( "_" ), F.col( "salt" ))) other_df = other_df.withColumn( "salt" , F.explode(F.array([F.lit(i) for i in range (SALT_BUCKETS)]))) \ .withColumn( "salted_key" , F.concat(F.col( "skewed_key" ), F.lit( "_" ), F.col( "salt" ))) result = skewed_df.join(other_df, on= "salted_key" , how= "inner" ) \ .drop( "salt" , "salted_key" ) Correct Caching Pattern # Cache ONLY when the DataFrame is reused multiple times df_cleaned = df. filter (...).withColumn(...).cache() df_cleaned.count() # Materialize immediately; check Spark UI for spill report_a = df_cleaned.groupBy( "region" ).agg(...) report_b = df_cleaned.groupBy( "product" ).agg(...) df_cleaned.unpersist() # Release when done Constraints MUST DO Use DataFrame API over RDD for structured data processing Define explicit schemas for production pipelines Partition data appropriately (200-1000 partitions per executor core) Cache intermediate results only when reused multiple times Use broadcast joins for small dimension tables (<200MB) Handle data skew with salting or custom partitioning Monitor Spark UI for shuffle, spill, and GC metrics Test with production-scale data volumes MUST NOT DO Use collect() on large datasets (causes OOM) Skip schema definition and rely on inference in production Cache every DataFrame without measuring benefit Ignore shuffle partition tuning (default 200 often wrong) Use UDFs when built-in functions available (10-100x slower) Process small files without coalescing (small file problem) Run transformations without understanding lazy evaluation Ignore data skew warnings in Spark UI Output Templates When implementing Spark solutions, provide: Complete Spark code (PySpark or Scala) with type hints/types Configuration recommendations (executors, memory, shuffle partitions) Partitioning strategy explanation Performance analysis (expected shuffle size, memory usage) Monitoring recommendations (key Spark UI metrics to watch) Knowledge Reference Spark DataFrame API, Spark SQL, RDD transformations/actions, catalyst optimizer, tungsten execution engine, partitioning strategies, broadcast variables, accumulators, structured streaming, watermarks, checkpointing, Spark UI analysis, memory management, shuffle optimization Documentation