org.apache.spark.sql.catalyst.expressions.aggregate
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package aggregate
A helper class for representing an attribute used in merging two aggregation buffers.
A helper class for representing an attribute used in merging two
aggregation buffers. When merging two buffers, bufferLeft and bufferRight,
we merge buffer values and then update bufferLeft. A RichAttribute
of an AttributeReference a has two functions left and right,
which represent a in bufferLeft and bufferRight, respectively.
Attributes of fields in aggBufferSchema.
Attributes of fields in aggBufferSchema.
An expression-based aggregate's bufferSchema is derived from bufferAttributes.
An expression-based aggregate's bufferSchema is derived from bufferAttributes.
Returns the tree node at the specified number.
Returns the tree node at the specified number. Numbers for each node can be found in the numberedTreeString.
Returns a string representing the arguments to this node, minus any children
Returns a string representing the arguments to this node, minus any children
Returns a 'scala code' representation of this TreeNode and its children.
Returns a 'scala code' representation of this TreeNode and its children. Intended for use
when debugging where the prettier toString function is obfuscating the actual structure. In the
case of 'pure' TreeNodes that only contain primitives and other TreeNodes, the result can be
pasted in the REPL to build an equivalent Tree.
Returns an expression where a best effort attempt has been made to transform this in a way
that preserves the result but removes cosmetic variations (case sensitivity, ordering for
commutative operations, etc.) See Canonicalize for more details.
Returns an expression where a best effort attempt has been made to transform this in a way
that preserves the result but removes cosmetic variations (case sensitivity, ordering for
commutative operations, etc.) See Canonicalize for more details.
deterministic expressions where this.canonicalized == other.canonicalized will always
evaluate to the same result.
Checks the input data types, returns TypeCheckResult.success if it's valid,
or returns a TypeCheckResult with an error message if invalid.
Checks the input data types, returns TypeCheckResult.success if it's valid,
or returns a TypeCheckResult with an error message if invalid.
Note: it's not valid to call this method until childrenResolved == true.
Returns a Seq of the children of this node.
Returns true if all the children of this expression have been resolved to a specific schema and false if any still contains any unresolved placeholders.
Returns true if all the children of this expression have been resolved to a specific schema and false if any still contains any unresolved placeholders.
Returns a Seq containing the result of applying a partial function to all elements in this tree on which the function is defined.
Returns a Seq containing the result of applying a partial function to all elements in this tree on which the function is defined.
Finds and returns the first TreeNode of the tree for which the given partial function is defined (pre-order), and applies the partial function to it.
Returns the DataType of the result of evaluating this expression.
Returns the DataType of the result of evaluating this expression. It is
invalid to query the dataType of an unresolved expression (i.e., when resolved == false).
Result of the aggregate function when the input is empty.
Result of the aggregate function when the input is empty. This is currently only used for the proper rewriting of distinct aggregate functions.
Returns true when the current expression always return the same result for fixed inputs from children.
Returns true when the current expression always return the same result for fixed inputs from children.
Note that this means that an expression should be considered as non-deterministic if: - if it relies on some mutable internal state, or - if it relies on some implicit input that is not part of the children expression list. - if it has non-deterministic child or children.
An example would be SparkPartitionID that relies on the partition id returned by TaskContext.
By default leaf expressions are deterministic as Nil.forall(_.deterministic) returns true.
Returns Java source code that can be compiled to evaluate this expression.
Returns Java source code that can be compiled to evaluate this expression. The default behavior is to call the eval method of the expression. Concrete expression implementations should override this to do actual code generation.
a CodegenContext
an ExprCode with unique terms.
an ExprCode containing the Java source code to generate the given expression
Returns the result of evaluating this expression on a given input Row
Returns the result of evaluating this expression on a given input Row
An expression which returns the final value for this aggregate function.
An expression which returns the final value for this aggregate function. Its data type should match this expression's dataType.
Faster version of equality which short-circuits when two treeNodes are the same instance.
Faster version of equality which short-circuits when two treeNodes are the same instance.
We don't just override Object.equals, as doing so prevents the scala compiler from
generating case class equals methods
Find the first TreeNode that satisfies the condition specified by f.
Returns a Seq by applying a function to all nodes in this tree and using the elements of the resulting collections.
Returns a Seq by applying a function to all nodes in this tree and using the elements of the resulting collections.
An aggregate function is not foldable.
An aggregate function is not foldable.
Runs the given function on this node and then recursively on children.
Runs the given function recursively on children then on this node.
Returns an ExprCode, that contains the Java source code to generate the result of evaluating the expression on an input row.
Returns an ExprCode, that contains the Java source code to generate the result of evaluating the expression on an input row.
a CodegenContext
ExprCode
Appends the string represent of this node and its children to the given StringBuilder.
Appends the string represent of this node and its children to the given StringBuilder.
The i-th element in lastChildren indicates whether the ancestor of the current node at
depth i + 1 is the last child of its own parent node. The depth of the root node is 0, and
lastChildren for the root node should be empty.
Expressions for initializing empty aggregation buffers.
Expressions for initializing empty aggregation buffers.
All the nodes that are parts of this node.
All the nodes that are parts of this node.
For example:
WholeStageCodegen +- SortMergeJoin |-- InputAdapter | +-- Sort +-- InputAdapter +-- Sort
the innerChildren of WholeStageCodegen will be Seq(SortMergeJoin), it will generate a tree string like this:
WholeStageCodegen : +- SortMergeJoin : :- INPUT : :- INPUT :- Sort :- Sort
Attributes of fields in input aggregation buffers (immutable aggregation buffers that are merged with mutable aggregation buffers in the merge() function or merge expressions).
Attributes of fields in input aggregation buffers (immutable aggregation buffers that are merged with mutable aggregation buffers in the merge() function or merge expressions). These attributes are created automatically by cloning the aggBufferAttributes.
Expected input types from child expressions.
Expected input types from child expressions. The i-th position in the returned seq indicates the type requirement for the i-th child.
The possible values at each position are: 1. a specific data type, e.g. LongType, StringType. 2. a non-leaf abstract data type, e.g. NumericType, IntegralType, FractionalType.
Creates a copy of this type of tree node after a transformation.
Creates a copy of this type of tree node after a transformation. Must be overridden by child classes that have constructor arguments that are not present in the productIterator.
the new product arguments.
Returns a Seq containing the result of applying the given function to each node in this tree in a preorder traversal.
Returns a Seq containing the result of applying the given function to each node in this tree in a preorder traversal.
the function to be applied.
Returns a copy of this node where f has been applied to all the nodes children.
Returns a copy of this node where f has been applied to all the nodes children.
A sequence of expressions for merging two aggregation buffers together.
A sequence of expressions for merging two aggregation buffers together. When defining these
expressions, you can use the syntax attributeName.left and attributeName.right to refer
to the attributes corresponding to each of the buffers being merged (this magic is enabled
by the RichAttribute implicit class).
Returns the name of this type of TreeNode.
Returns the name of this type of TreeNode. Defaults to the class name. Note that we remove the "Exec" suffix for physical operators here.
Returns a string representation of the nodes in this tree, where each operator is numbered.
Args to the constructor that should be copied, but not transformed.
Args to the constructor that should be copied, but not transformed. These are appended to the transformed args automatically by makeCopy
Returns a user-facing string representation of this expression's name.
Returns a user-facing string representation of this expression's name. This should usually match the name of the function in SQL.
Returns true if this expression and all its children have been resolved to a specific schema
and input data types checking passed, and false if it still contains any unresolved
placeholders or has data types mismatch.
Returns true if this expression and all its children have been resolved to a specific schema
and input data types checking passed, and false if it still contains any unresolved
placeholders or has data types mismatch.
Implementations of expressions should override this if the resolution of this type of
expression involves more than just the resolution of its children and type checking.
Returns true when two expressions will always compute the same result, even if they differ cosmetically (i.e.
Returns true when two expressions will always compute the same result, even if they differ cosmetically (i.e. capitalization of names in attributes may be different).
See Canonicalize for more details.
Returns a hashCode for the calculation performed by this expression.
Returns a hashCode for the calculation performed by this expression. Unlike the standard
hashCode, an attempt has been made to eliminate cosmetic differences.
See Canonicalize for more details.
String representation of this node without any children.
String representation of this node without any children.
Returns SQL representation of this expression.
Returns SQL representation of this expression. For expressions extending NonSQLExpression, this method may return an arbitrary user facing string.
The arguments that should be included in the arg string.
The arguments that should be included in the arg string. Defaults to the productIterator.
Indicates if this function supports partial aggregation.
Indicates if this function supports partial aggregation. Currently Hive UDAF is the only one that doesn't support partial aggregation.
Wraps this AggregateFunction in an AggregateExpression and set isDistinct field of the AggregateExpression to the given value because AggregateExpression is the container of an AggregateFunction, aggregation mode, and the flag indicating if this aggregation is distinct aggregation or not.
Wraps this AggregateFunction in an AggregateExpression and set isDistinct field of the AggregateExpression to the given value because AggregateExpression is the container of an AggregateFunction, aggregation mode, and the flag indicating if this aggregation is distinct aggregation or not. An AggregateFunction should not be used without being wrapped in an AggregateExpression.
Wraps this AggregateFunction in an AggregateExpression because AggregateExpression is the container of an AggregateFunction, aggregation mode, and the flag indicating if this aggregation is distinct aggregation or not.
Wraps this AggregateFunction in an AggregateExpression because AggregateExpression is the container of an AggregateFunction, aggregation mode, and the flag indicating if this aggregation is distinct aggregation or not. An AggregateFunction should not be used without being wrapped in an AggregateExpression.
Returns a copy of this node where rule has been recursively applied to the tree.
Returns a copy of this node where rule has been recursively applied to the tree.
When rule does not apply to a given node it is left unchanged.
Users should not expect a specific directionality. If a specific directionality is needed,
transformDown or transformUp should be used.
the function use to transform this nodes children
Returns a copy of this node where rule has been recursively applied to all the children of
this node.
Returns a copy of this node where rule has been recursively applied to all the children of
this node. When rule does not apply to a given node it is left unchanged.
the function used to transform this nodes children
Returns a copy of this node where rule has been recursively applied to it and all of its
children (pre-order).
Returns a copy of this node where rule has been recursively applied to it and all of its
children (pre-order). When rule does not apply to a given node it is left unchanged.
the function used to transform this nodes children
Returns a copy of this node where rule has been recursively applied first to all of its
children and then itself (post-order).
Returns a copy of this node where rule has been recursively applied first to all of its
children and then itself (post-order). When rule does not apply to a given node, it is left
unchanged.
the function use to transform this nodes children
All the nodes that will be used to generate tree string.
All the nodes that will be used to generate tree string.
For example:
WholeStageCodegen +-- SortMergeJoin |-- InputAdapter | +-- Sort +-- InputAdapter +-- Sort
the treeChildren of WholeStageCodegen will be Seq(Sort, Sort), it will generate a tree string like this:
WholeStageCodegen : +- SortMergeJoin : :- INPUT : :- INPUT :- Sort :- Sort
Returns a string representation of the nodes in this tree
Returns a string representation of the nodes in this tree
Expressions for updating the mutable aggregation buffer based on an input row.
Expressions for updating the mutable aggregation buffer based on an input row.
Returns a copy of this node with the children replaced.
Returns a copy of this node with the children replaced. TODO: Validate somewhere (in debug mode?) that children are ordered correctly.
Returns the first value of
childfor a group of rows. If the first value ofchildisnull, it returnsnull(respecting nulls). Even if First is used on a already sorted column, if we do partial aggregation and final aggregation (when mergeExpression is used) its result will not be deterministic (unless the input table is sorted and has a single partition, and we use a single reducer to do the aggregation.).