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

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

    [ https://issues.apache.org/jira/browse/OPTIQ-344?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14074754#comment-14074754 ] 

Julian Hyde commented on OPTIQ-344:
-----------------------------------

Working on this in https://github.com/julianhyde/optiq/commits/optiq-344.

> 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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