[CALCITE-302] Use heuristic rule to plan queries with large numbers of joins

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.8
• Labels: github-import
• Assignee: Unassigned
• Reporter: GitHub Import
• Created: 18/Jun/14 09:05
• Updated: 25/Aug/14 19:08
• Resolved: 22/Jun/14 00:53

Description

If a query has a large number of joins, the planning time and space grows exponentially in N, the number of joins. About about N=8 it is not possible to plan a query exhaustively.

`LoptOptimizeJoinRule` is a heuristic join rule that uses a greedy algorithm. It operates on a `MultiJoinRel`, which must first have been created using `ConvertMultiJoinRule`. Enabling this rule, and disable the join transformation rules `SwapJoinRule` and `PushJoinThroughJoinRule`, it is possible to plan queries with N=60 and higher.

---------------- Imported from GitHub ----------------
Url: https://github.com/julianhyde/optiq/issues/302
Created by: julianhyde
Labels:
Created at: Wed Jun 18 03:27:16 CEST 2014
State: open