Module com.darkcollective.relix.processor

Package com.darkcollective.relix.processor.exec

package com.darkcollective.relix.processor.exec

Execution operators for the relix processor.

This package contains the recursive RelNodeExecutor that walks a RelNode tree and produces a lazy Stream<Row> pipeline. All 21 node types of the sealed RelNode hierarchy are implemented.

Streaming vs. materialising operators

Unary streaming operators (Selection, Projection, Rename, Limit, Distinct, UnionAll) chain directly onto the input stream without intermediate materialisation.

Operators that require full materialisation collect the input into an appropriate MaterializedRelation collection type before returning a fresh stream:

• BagRelation — ordered, duplicates allowed (Sort, Aggregation, UnionAll output, outer-join unmatched rows)
• SetRelation — insertion-order, deduplicated (Union, Intersection, Difference)
• SortedBagRelation — sorted, duplicates allowed (Sort output)
• IndexedRelation — grouped by key (Aggregation intermediate)

Binary join algorithms

All joins use nested-loop. The right-hand side is always fully materialised; the left-hand side is streamed where possible (Product, ThetaJoin, LeftOuterJoin, SemiJoin, AntiJoin) and materialised where the algorithm requires random access (NaturalJoin, RightOuterJoin, FullOuterJoin).

Set operations

Union deduplicates via SetRelation. Intersection and Difference materialise the right side as a set for O(1) membership tests while streaming the left side. Division uses the nested-loop "for-all" check with a hash-set lookup of full left-row tuples.

Related Packages

Package	Description
com.darkcollective.relix.processor	Row: one row of a result, a tuple of Values read by position or by column name.
com.darkcollective.relix.processor.connector	The connector provider interface, and connector plugin provisioning.
com.darkcollective.relix.processor.eval	Scalar expression and predicate evaluation for query execution.
com.darkcollective.relix.processor.generator	Generator relations — leaf relations whose rows are produced by engine code rather than read from a file or database.
com.darkcollective.relix.processor.internal	The engine-side machinery behind com.darkcollective.relix.processor: not exported by the published artifact.
com.darkcollective.relix.processor.provenance	A relation annotated over a semiring, as Relation.provenance returns it.

Class	Description
BagRelation	A materialised relation that preserves insertion order and allows duplicate rows — the Bag type in the IBM flat-collection taxonomy.
IndexedRelation	A materialised relation whose rows are partitioned into groups by a composite key — the Relation type in the IBM flat-collection taxonomy (Key, Element Equality, Unordered, Multiple).
MaterializedRelation	A relation that has been fully materialised into an in-memory collection.
PhysicalExecutor	Executes a PhysicalNode plan, producing a lazy Stream<Row >.
QualifiedRow	A read-only positional view over a left row concatenated with a right row, used to evaluate a join condition with correct handling of qualified attribute references.
RelNodeExecutor	Executes a logical relational algebra RelNode tree.
SetRelation	A materialised relation that contains only unique rows, preserving the order in which rows were first inserted — the Set type in the IBM flat-collection taxonomy (No Key, Element Equality, Unordered, Unique).
SortedBagRelation	A materialised relation whose rows are kept in a stable sorted order and may contain duplicates — the Sorted bag type in the IBM flat-collection taxonomy (No Key, No Element Equality required, Sorted, Multiple).