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https://issues.apache.org/jira/browse/HIVE-23006?focusedWorklogId=418825&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-418825
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ASF GitHub Bot logged work on HIVE-23006:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 08/Apr/20 19:42
Start Date: 08/Apr/20 19:42
Worklog Time Spent: 10m
Work Description: jcamachor commented on pull request #952: HIVE-23006
ProbeDecode compiler support
URL: https://github.com/apache/hive/pull/952#discussion_r405769389
##########
File path:
ql/src/java/org/apache/hadoop/hive/ql/optimizer/SharedWorkOptimizer.java
##########
@@ -487,6 +487,15 @@ private static boolean
sharedWorkOptimization(ParseContext pctx, SharedWorkOptim
}
LOG.debug("Input operator removed: {}", op);
}
+
+ // A shared TSop across branches can not have probeContext that
utilizes single branch info
+ // Filtered-out rows from one branch might be needed by another
branch sharing a TSop
+ if (retainableTsOp.getProbeDecodeContext() != null) {
Review comment:
In this case, should we remove the `ProbeDecodeContext` or should we skip
merging these two TS operators? It may be that in some cases merging will
backfire, i.e., if those two filters were very selective? Just for reference,
if I remember correctly, SharedWorkOptimizer only merges TS operators targeted
by SJs if at least one of the TS operators do not contain a SJ (since we would
incur the full scan cost in any case at least once).
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Issue Time Tracking
-------------------
Worklog Id: (was: 418825)
Time Spent: 2h 10m (was: 2h)
> Compiler support for Probe MapJoin
> ----------------------------------
>
> Key: HIVE-23006
> URL: https://issues.apache.org/jira/browse/HIVE-23006
> Project: Hive
> Issue Type: Sub-task
> Reporter: Panagiotis Garefalakis
> Assignee: Panagiotis Garefalakis
> Priority: Major
> Labels: pull-request-available
> Attachments: HIVE-23006.01.patch, HIVE-23006.02.patch
>
> Time Spent: 2h 10m
> Remaining Estimate: 0h
>
> The decision of pushing down information to the Record reader (potentially
> reducing decoding time by row-level filtering) should be done at query
> compilation time.
> This patch adds an extra optimisation step with the goal of finding Table
> Scan operators that could reduce the number of rows decoded at runtime using
> extra available information.
> It currently looks for all the available MapJoin operators that could use the
> smaller HashTable on the probing side (where TS is) to filter-out rows that
> would never match.
> To do so the HashTable information is pushed down to the TS properties and
> then propagated as part of MapWork.
> If the a single TS is used by multiple operators (shared-word), this rule can
> not be applied.
> This rule can be extended to support static filter expressions like:
> _select * from sales where sold_state = 'PR';_
> This optimisation manly targets the Tez execution engine running on Llap.
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