[IGNITE-7541] SQL COPY command: implement backend switching option

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Component/s: sql
• Assignee: Unassigned
• Reporter: Kirill Shirokov
• Created: 25/Jan/18 16:18
• Updated: 14/Feb/19 15:12
• Resolved: 14/Feb/19 15:12

Description

When we load data using COPY command we can add key/value pairs to the cache using different ways:

• Directly calling cache.putAll()
• Loading data via DataStreamer
• etc.

Every backend has its pros and cons. For example, the streamer is fast and asynchronous, although it cannot replace value and cannot provide any statistics – such as number of added records. The direct interface is slow and synchronous, but provides us with an ability to either replace or skip the records with the same key and respond to the user with full statistics.

There shall be an option in the SQL command to switch to particular backend. For example:

COPY
    FROM 'file'
    ...
    [BACKEND (DIRECT | STREAMER)]

We might have more backends in the future.

Issue Links

• is blocked by: IGNITE-6917 SQL: implement COPY command for efficient data loading
• is related to: IGNITE-7735 SQL COPY: expose streamer options to user