[HIVE-6901] Explain plan doesn't show operator tree for the fetch operator

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.12.0
• Fix Version/s: 0.14.0
• Component/s: Query Processor
• Assignee: Xuefu Zhang
• Reporter: Xuefu Zhang
• Created: 12/Apr/14 02:30
• Updated: 13/Nov/14 19:43
• Resolved: 13/May/14 16:36

Description

Explaining a simple select query that involves a MR phase doesn't show processor tree for the fetch operator.

hive> explain select d from test;
OK
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-0 is a root stage

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
...
  Stage: Stage-0
    Fetch Operator
      limit: -1

It would be nice if the operator tree is shown even if there is only one node.

Please note that in local execution, the operator tree is complete:

hive> explain select * from test;
OK
STAGE DEPENDENCIES:
  Stage-0 is a root stage

STAGE PLANS:
  Stage: Stage-0
    Fetch Operator
      limit: -1
      Processor Tree:
        TableScan
          alias: test
          Statistics: Num rows: 8 Data size: 34 Basic stats: COMPLETE Column stats: NONE
          Select Operator
            expressions: d (type: int)
            outputColumnNames: _col0
            Statistics: Num rows: 8 Data size: 34 Basic stats: COMPLETE Column stats: NONE
            ListSink

Issue Links

• is related to: HIVE-3925 dependencies of fetch task are not shown by explain