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https://issues.apache.org/jira/browse/IMPALA-14101?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18017942#comment-18017942
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ASF subversion and git services commented on IMPALA-14101:
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Commit e74495e65652fed124afe58cdeb984e1d3a528bc in impala's branch
refs/heads/master from Steve Carlin
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=e74495e65 ]
IMPALA-14101: [part 2] Calcite planner: Add cost model calculations
This commit adds the cost model and calculations to be used in the join
optimizer rule. The ImpalaCost object implements the RelOptCost interface
and contains values which contribute to a cost. The ImpalaCost object
roughly mirrors the Calcite VolcanoCost object with some slight variations.
The ImpalaCost object only looks at the cpu and io cost and ignores the
rowCount cost. The rowCount cost is not needed because it is already
baked into the cpu and io results. That is to say, we determine the cpu cost
and io cost by using the rowCount cost.
The ImpalaCost object is generated in the ImpalaRelMdNonCumulativeCost
class which is called from Calcite for a given RelNode. The cost generated
by this object uses the various inputs of the RelNode to calculate the
cpu and io time for the given logical node. Note that this is a
non-cumulative cost. A cumulative cost exists within Calcite as well, but
there was no need to change the cumulative cost logic.
The cost is used by the Calcite LoptOptimizeJoinRule when determining join
ordering. It will compare costs of different join ordering and choose the
join ordering with a lower cost.
With the current iteration, we only customize the costs for Impala for
aggregates, table scans, and joins.
A TODO in this commit is to allow various cpu and io costs to be configurable.
Change-Id: I1e52b0e11e9a6d5814b0313117dd9c56602f3ff5
Reviewed-on: http://gerrit.cloudera.org:8080/23311
Reviewed-by: Riza Suminto <[email protected]>
Reviewed-by: Michael Smith <[email protected]>
Tested-by: Riza Suminto <[email protected]>
> Calcite Planner: Add Calcite cost model calculations
> ----------------------------------------------------
>
> Key: IMPALA-14101
> URL: https://issues.apache.org/jira/browse/IMPALA-14101
> Project: IMPALA
> Issue Type: Sub-task
> Reporter: Steve Carlin
> Assignee: Steve Carlin
> Priority: Major
>
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