[jira] [Resolved] (TAJO-1342) The complex join query runs forever

["Jihoon Son (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TAJO-1342?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jihoon Son resolved TAJO-1342.
------------------------------
    Resolution: Cannot Reproduce

> The complex join query runs forever
> -----------------------------------
>
>                 Key: TAJO-1342
>                 URL: https://issues.apache.org/jira/browse/TAJO-1342
>             Project: Tajo
>          Issue Type: Bug
>            Reporter: Jihoon Son
>
> TAJO-1277 fixes a bug of join ordering which ignores the different associativity according to the join types.
> After TAJO-1277, I found an additional hidden bug. Please see the following example.
> {noformat}
> default> select * from customer right outer join supplier on c_nationkey = s_nationkey inner join nation on n_nationkey = c_nationkey full outer join region on n_regionkey = r_regionkey;
> Progress: 0%, response time: 1.632 sec
> Progress: 0%, response time: 1.633 sec
> Progress: 0%, response time: 2.038 sec
> Progress: 0%, response time: 2.843 sec
> Progress: 98%, response time: 3.848 sec
> Progress: 98%, response time: 4.854 sec
> ...
> (Infinitely repeated)
> {noformat}
> The join order of this query is: 
> {noformat}
> (((default.customer ⟖ default.supplier) ⋈θ default.nation) ⟗ default.region)
> {noformat}
> Here is the query master log
> {noformat}
> ...
> 2015-02-11 12:30:33,987 INFO org.apache.tajo.engine.planner.PhysicalPlannerImpl: Right Outer Join (9) chooses [Hash Join].
> 2015-02-11 12:30:33,990 INFO org.apache.tajo.engine.planner.PhysicalPlannerImpl: [ta_1423625266462_0001_000003_000000_00] the volume of Left relations (eb_1423625266462_0001_000001, eb_1423625266462_0001_000002) is 24.8 MiB and is fit to main maemory.
> 2015-02-11 12:30:33,990 INFO org.apache.tajo.engine.planner.PhysicalPlannerImpl: Join (10) chooses [In-memory Hash Join]
> 2015-02-11 12:30:33,990 INFO org.apache.tajo.engine.planner.PhysicalPlannerImpl: [ta_1423625266462_0001_000003_000000_00] Right relations default.nation (2.2 KiB) is smaller than Left relations eb_1423625266462_0001_000001, eb_1423625266462_0001_000002 (24.8 MiB).
> 2015-02-11 12:30:33,991 INFO org.apache.tajo.engine.planner.PhysicalPlannerImpl: Full Outer Join (11) chooses [Hash Join]
> {noformat}
> As you can see, the query master seems to fall into an infinite loop during executing the hash outer join.
> This bug is not found in the current master branch. The difference is found in the join order as follows:
> {noformat}
> (((default.nation ⟗ default.region) ⋈θ default.customer) ⟖ default.supplier)
> {noformat}



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