Packages

package root

Definition Classes: root

package org

Definition Classes: root

package apache

Definition Classes: org

package spark

Definition Classes: apache

package sql

Definition Classes: spark

package catalyst

Catalyst is a library for manipulating relational query plans.

Catalyst is a library for manipulating relational query plans. All classes in catalyst are considered an internal API to Spark SQL and are subject to change between minor releases.

Definition Classes: sql

package analysis

Provides a logical query plan Analyzer and supporting classes for performing analysis.

Provides a logical query plan Analyzer and supporting classes for performing analysis. Analysis consists of translating UnresolvedAttributes and UnresolvedRelations into fully typed objects using information in a schema Catalog.

Definition Classes: catalyst

package catalog

Definition Classes: catalyst

package csv

Definition Classes: catalyst

package dsl

A collection of implicit conversions that create a DSL for constructing catalyst data structures.

scala> import org.apache.spark.sql.catalyst.dsl.expressions._

// Standard operators are added to expressions.
scala> import org.apache.spark.sql.catalyst.expressions.Literal
scala> Literal(1) + Literal(1)
res0: org.apache.spark.sql.catalyst.expressions.Add = (1 + 1)

// There is a conversion from 'symbols to unresolved attributes.
scala> 'a.attr
res1: org.apache.spark.sql.catalyst.analysis.UnresolvedAttribute = 'a

// These unresolved attributes can be used to create more complicated expressions.
scala> 'a === 'b
res2: org.apache.spark.sql.catalyst.expressions.EqualTo = ('a = 'b)

// SQL verbs can be used to construct logical query plans.
scala> import org.apache.spark.sql.catalyst.plans.logical._
scala> import org.apache.spark.sql.catalyst.dsl.plans._
scala> LocalRelation($"key".int, $"value".string).where('key === 1).select('value).analyze
res3: org.apache.spark.sql.catalyst.plans.logical.LogicalPlan =
Project [value#3]
 Filter (key#2 = 1)
  LocalRelation [key#2,value#3], []

Definition Classes: catalyst

package encoders

Definition Classes: catalyst

package expressions

A set of classes that can be used to represent trees of relational expressions.

A set of classes that can be used to represent trees of relational expressions. A key goal of the expression library is to hide the details of naming and scoping from developers who want to manipulate trees of relational operators. As such, the library defines a special type of expression, a NamedExpression in addition to the standard collection of expressions.

Standard Expressions

A library of standard expressions (e.g., Add, EqualTo), aggregates (e.g., SUM, COUNT), and other computations (e.g. UDFs). Each expression type is capable of determining its output schema as a function of its children's output schema.

Named Expressions

Some expression are named and thus can be referenced by later operators in the dataflow graph. The two types of named expressions are AttributeReferences and Aliases. AttributeReferences refer to attributes of the input tuple for a given operator and form the leaves of some expression trees. Aliases assign a name to intermediate computations. For example, in the SQL statement SELECT a+b AS c FROM ..., the expressions a and b would be represented by AttributeReferences and c would be represented by an Alias.

During analysis, all named expressions are assigned a globally unique expression id, which can be used for equality comparisons. While the original names are kept around for debugging purposes, they should never be used to check if two attributes refer to the same value, as plan transformations can result in the introduction of naming ambiguity. For example, consider a plan that contains subqueries, both of which are reading from the same table. If an optimization removes the subqueries, scoping information would be destroyed, eliminating the ability to reason about which subquery produced a given attribute.

Evaluation

The result of expressions can be evaluated using the Expression.apply(Row) method.

Definition Classes: catalyst

package json

Definition Classes: catalyst

package optimizer

Definition Classes: catalyst

package parser

Definition Classes: catalyst

package planning

Contains classes for enumerating possible physical plans for a given logical query plan.

Definition Classes: catalyst

package plans

A collection of common abstractions for query plans as well as a base logical plan representation.

Definition Classes: catalyst

package rules

A framework for applying batches rewrite rules to trees, possibly to fixed point.

Definition Classes: catalyst

package streaming

Definition Classes: catalyst

package trees

A library for easily manipulating trees of operators.

A library for easily manipulating trees of operators. Operators that extend TreeNode are granted the following interface:

Scala collection like methods (foreach, map, flatMap, collect, etc)

- transform - accepts a partial function that is used to generate a new tree. When the partial function can be applied to a given tree segment, that segment is replaced with the result. After attempting to apply the partial function to a given node, the transform function recursively attempts to apply the function to that node's children.