[IMPALA-10970] Coordinator only query judgement logic should concern separated join build execution

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 4.0.0
• Fix Version/s: Impala 4.1.0
• Epic Color: ghx-label-1
• Assignee: guojingfeng
• Reporter: guojingfeng
• Created: 17/Oct/21 05:06
• Updated: 08/Dec/21 03:27
• Resolved: 08/Dec/21 03:27

Description

IMPALA-8830 introduce the ability of executing trivail queries regardless the healthness of executor groups. Coordinatory only query judgment logic controls that whether a quer is trivail query or not. It take the query ExecRequest and check the plan only contains a single unpartitioned fragment. But join builder is scheduled at a separated fragment and colocated with join node after IMPALA-4224, in this case a query plan will contain two PlenExecInfo. I think the coorinator only judgment logic should also check the jon build side of the total execution plan.

Here is a bad case with query option MT_DOP>0: 

SELECT
STRAIGHT_JOIN * // Add straight_join hint to disable optimization
FROM
    ( SELECT '20210831' AS ts
     UNION ALL SELECT '20210901' AS ts
     UNION ALL SELECT '20210902' AS ts
     UNION ALL SELECT '20210903' AS ts ) t1
CROSS JOIN tpch.lineitem t2
LIMIT 100;

In debug build this query will fail and got core dump at hit the DECHECK at
/be/src/scheduling/scheduler.cc#L162

DCHECK(executor_config.group.NumExecutors() > 0 || exec_at_coord);

In release build this query will fail with message "Scheduling for executor group: empty group
(using coordinator only) with 0 executors"