[IGNITE-6072] SQL: client node should not hold the whole data set in-memory when possible when merge table is there

• Type: Task
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 2.1
• Component/s: sql
• Assignee: Unassigned
• Reporter: Vladimir Ozerov
• Created: 16/Aug/17 06:51
• Updated: 14/Feb/19 08:15
• Resolved: 14/Feb/19 08:15

Description

We implemented a fix for a case without merge table (IGNITE-6019). Let's try to do the same for merge table case. Essentially, we need to split all queries into two groups:

• Blocking - i.e. it require the whole result set from mappers first
• Non-blocking - everything what is not blocking

Fix should be applied only to non-blocking case. Raw estimation from my side, what is "blocking":
1) GROUP BY/HAVING
2) DISTINCT
3) LIMIT/OFFSET
4) Subqueries

Issue Links

• is related to: IGNITE-6019 SQL: client node should not hold the whole data set in-memory when possible