[DRILL-7733] Use streaming for REST JSON queries

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.17.0
• Fix Version/s: 1.19.0
• Assignee: Paul Rogers
• Reporter: Paul Rogers
• Reviewer: Vova Vysotskyi
• Created: 05/May/20 23:24
• Updated: 04/Mar/21 05:17
• Resolved: 30/Jan/21 02:47

Description

Several uses on the user and dev mail lists have complained about the memory overhead when running a REST JSON query: http:://node:8047/query.json. The current implementation buffers the entire result set in memory, then lets Jersey/Jetty convert the results to JSON. The result is very heavy heap use for larger query result sets.

This ticket requests a change to use streaming. As each batch arrives at the Screen operator, convert that batch to JSON and directly stream the results to the client network connection, much as is done for the native client connection.

For backward compatibility, the form of the JSON must be the same as the current API.

Issue Links

• fixes: DRILL-7872 Heap memory within docker container does not get recycled