Greg Hogan created FLINK-3910: --------------------------------- Summary: New self-join operator Key: FLINK-3910 URL: https://issues.apache.org/jira/browse/FLINK-3910 Project: Flink Issue Type: New Feature Components: DataSet API, Java API, Scala API Affects Versions: 1.1.0 Reporter: Greg Hogan Assignee: Greg Hogan
Flink currently provides inner- and outer-joins as well as cogroup and the non-keyed cross. {{JoinOperator}} hints at future support for semi- and anti-joins. Many Gelly algorithms perform a self-join [0]. Still pending reviews, FLINK-3768 performs a self-join on non-skewed data in TriangleListing.java and FLINK-3780 performs a self-join on skewed data in JaccardSimilarity.java. A {{SelfJoinHint}} will select between skewed and non-skewed implementations. The object-reuse-disabled case can be simply handled with a new {{Operator}}. The object-reuse-enabled case requires either {{CopyableValue}} types (as in the code above) or a custom driver which has access to the serializer (or making the serializer accessible to rich functions, and I think there be dragons). If the idea of a self-join is agreeable, I'd like to work out a rough implementation and go from there. [0] https://en.wikipedia.org/wiki/Join_%28SQL%29#Self-join -- This message was sent by Atlassian JIRA (v6.3.4#6332)