[jira] [Created] (OPTIQ-344) Lattice data structure

["Julian Hyde (JIRA)" <ji...@apache.org>]

Julian Hyde created OPTIQ-344:
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             Summary: Lattice data structure
                 Key: OPTIQ-344
                 URL: https://issues.apache.org/jira/browse/OPTIQ-344
             Project: Optiq
          Issue Type: New Feature
            Reporter: Julian Hyde
            Assignee: Julian Hyde


Add a "lattice" data structure, to organize, gather statistics on, and recommend materialized queries.

DDL. Here is a possible SQL DDL syntax:

CREATE LATTICE SalesStar AS
SELECT *
FROM SalesFact AS s
JOIN TimeDim AS t USING (timeId)
JOIN CustomerDim AS c USING (customerId)

Structure. A materialized query would optionally belong to a lattice.

Constraints. Creating a lattice implies that the first table is the fact table of a star schema, and all joins are many-to-one. That is, foreign keys, primary keys and NOT NULL constraints are implied.

Statistics. When queries arrive that could use a lattice, a counter is incremented.

Recommendation. An agent could recommend materialized queries to create based on static analysis of the star schema (e.g. table and column cardinalities), and perhaps statistics of past use.

View matching. The optimizer uses a lattice to identify materialized queries that could satisfy a query. (Without a lattice, the such space would be much larger, because the optimizer would have to consider many join permutations.)



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