[IGNITE-9480] SQL: Introduce H2 LocalResult factory

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.6
• Component/s: sql
• Labels: h2-limitation
• Ignite Flags: Docs Required
• Assignee: Unassigned
• Reporter: Taras Ledkov
• Created: 06/Sep/18 10:14
• Updated: 03/Jul/20 07:48

Description

H2 collects query result at the instance of `LocalResult` for queries results that not be gathered lazy. This causes an OOME error on large result sets.

We have to introduce way to use our own implementation of the query result's container.
Suggestion fix:

• H2 simple refactoring: make `LocalResult` interface and H2 default implementation `LocalResultImpl`
• Add H2 configurable `LocalResultFactory` to setup custom implementation of the `LocalResult.
• Create Ignite implementation of `LocalResultFactory` & `LocalResult` to track allocated memory, swap results to external storage etc.

H2 issue: #1405

Issue Links

• is related to: IGNITE-9616 SQL: Introduce H2 factory for holder of aggregate result
• relates to: IGNITE-7526 SQL: Introduce memory region for reducer merge results with disk offload
• links to: GitHub Pull Request #6090
• links to: H2 issue #1405 (Introduce LocalResult factory)
• links to: H2 pull request
• links to: Tests results