To protect the server from OOM, this PR introduces the limit for join operator to ensure the memory consumption is limited.

1. Add new query options for join operator right table size limit:

• joinOverflowMode(string) : Overflow mode, allowed value are: THROW/BREAK
  • Server config: pinot.query.join.overflow.mode=THROW
  • Session level: SET joinOverflowMode='THROW'
  • QueryHint level: join_overflow_mode='THROW'
• maxRowsInJoin(integer) : the number of rows allowed for right table cache in a join operator
  • Server config: pinot.query.join.max.rows=100000
  • Session level: SET maxRowsInJoin=1000000
  • QueryHint level: max_rows_in_join='1000000'

2. Add server partial result exception
3. Support continuous processing when joinOverflowMode = BREAK;

TODO: Support size based limit.

Examples:

SET joinOverflowMode='BREAK';
SET maxRowsInJoin=10;
SELECT a.playerName, a.teamID, b.teamName 
FROM baseballStats_OFFLINE AS a
JOIN dimBaseballTeams_OFFLINE AS b
ON a.teamID = b.teamID

SELECT /*+ joinOptions(join_overflow_mode='BREAK', max_rows_in_join='10') */ a.playerName, a.teamID, b.teamName 
FROM baseballStats_OFFLINE AS a
JOIN dimBaseballTeams_OFFLINE AS b
ON a.teamID = b.teamID

Sample screenshot for:
0. Normal run without limit hit: (Joined result is 47735)

1. Query option: Throw exception when row limit hit:

3. JoinHints: Throw exception when row limit hit:

4. JoinHints: Continue when row limit hit: (Joined result is 29884)

More examples of difference between the threshold, and overflow mode: