Spark SQL OptimizeCase 1: distribute by引起的shuffle起初有两张表进行join,但随着一张表的数据量增长,会导致task的运行时间很长,拖慢整个Job的运行过程,为了加快任务的运行,就增加大shuffle.partitions的大小,并且使用distribute by字段。 导致Job运行慢点原因:由于起初数据量小,默认设置的shuffle.partitions就很小,...
SparkOptimizer 优化:OptimizeIn(In to InSet) 技术标签:spark 查看原文 Spark SQL Catalyst源码分析之Optimizer MetastoreRelation default, src, None优化后:其实filter也可以表达为一个复杂的boolean表达式[java] view plain copy...,来对语法树进行优化,优化逻辑计划节点(Logical Plan)以及表达式(Expression),也是转换...
By design, Spark’s Catalyst engine automatically attempts to optimize a query to the fullest extent. However, any optimization effort is bound to fail if the query itself is badly written. For example, consider a query programmed to select all the columns of a Parquet/ORC table. Every column...
Optimize Spark performanceCompleted 100 XP 5 minutes Apache Spark is a distributed data processing framework that enables large-scale data analytics by coordinating work across multiple processing nodes in a cluster, known in Microsoft Fabric as a Spark pool. Put more simply, Spark uses a "div...
This optimization optimizes joins when using INTERSECT. With Amazon EMR 5.26.0, this feature is enabled by default. With Amazon EMR 5.24.0 and 5.25.0, you can enable it by setting the Spark propertyspark.sql.optimizer.distinctBeforeIntersect.enabledfrom within Spark or when creating clusters. ...
Optimize Spark performanceCompleted 100 XP 5 minutes Apache Spark is a distributed data processing framework that enables large-scale data analytics by coordinating work across multiple processing nodes in a cluster, known in Microsoft Fabric as a Spark pool. Put more simply, Spark uses a "...
Optimizer在org.apache.spark.sql.catalyst.optimize object DefaultOptimizerextendsOptimizer {//这里的batches是非常重要的,这里封装了每一个Spark SQL版本中,可以对逻辑执行计划执行的优化策略,在这里,重点理解Optimizer的各种优化策略//这样,才清楚,Spark SQL 内部是如何对我们写的SQL语句进行优化的,我们可以再编写SQL...
override def defaultBatches: Seq[Batch] = (preOptimizationBatches ++ super.defaultBatches :+ Batch("Optimize Metadata Only Query", Once, OptimizeMetadataOnlyQuery(catalog)) :+ Batch("Extract Python UDFs", Once, Seq(ExtractPythonUDFFromAggregate, ExtractPythonUDFs): _*) :+ Batch("Prune File Sou...
优化Optimize:生成最优执行计划 执行Execute:返回实际数据 SparkSQL对SQL语句的处理和关系型数据库采用了类似的方法, SparkSQL会先将SQL语句进行解析Parse形成一个Tree,然后使用Rule对Tree进行绑定、优化等处理过程,通过模式匹配对不同类型的节点采用不同的操作。而SparkSQL的查询优化器是Catalyst,它负责处理查询语句的解析...
该Batch 目前只包含 OptimizeSubqueries 这一条优化规则 。 5,Batch Replace Operators 该Batch 中的优化规则主要用来执行算子的替换操作。 6,Batch Aggregate 该Batch 主要用来处理聚合算子中的逻辑,包括 RemoveLit eralFrom GroupExpressions 和RemoveRepetitionFromGroupExpressions 两条规则 。