[IGNITE-9171] Use lazy mode with results pre-fetch

• Type: Task
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.6
• Fix Version/s: 2.8
• Component/s: sql
• Labels: sql-stability
• Assignee: Taras Ledkov
• Reporter: Taras Ledkov
• Created: 02/Aug/18 15:16
• Updated: 17/Feb/19 15:57
• Resolved: 17/Feb/19 15:51

Description

Current implementation of the lazy mode always starts separate thread for MapQueryLazyWorker. It causes excessive overhead for requests that produces small results set.

We have to begin execute query at the QUERY_POOL thread pool and fetch first page of the results. In case results set is bigger than one page MapQueryLazyWorker is started and link with MapNodeResults to handle next pages lazy.

Issue Links

• blocks: IGNITE-10829 MVCC TX: Lazy query execution for query enlists.
• is duplicated by: IGNITE-9864 CacheQueriesTest test fails in .NET
• is related to: IGNITE-9960 SQL: Revert and reopen lazy flag optimization (IGNITE-9171)
• is related to: IGNITE-10598 H2 ConnectionManager drop ThreadLocal logic
• relates to: IGNITE-11341 SQL: Enable lazy mode by default
• links to: dev-list thread
• links to: GitHub Pull Request #5473
• links to: GitHub Pull Request #5473
• links to: Tests results
• mentioned in: Page Loading...