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https://issues.apache.org/jira/browse/HIVE-23006?focusedWorklogId=419356&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-419356
]
ASF GitHub Bot logged work on HIVE-23006:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 09/Apr/20 11:50
Start Date: 09/Apr/20 11:50
Worklog Time Spent: 10m
Work Description: pgaref commented on pull request #952: HIVE-23006
ProbeDecode compiler support
URL: https://github.com/apache/hive/pull/952#discussion_r406148931
##########
File path: ql/src/java/org/apache/hadoop/hive/ql/parse/TezCompiler.java
##########
@@ -1483,17 +1489,64 @@ private void
removeSemijoinsParallelToMapJoin(OptimizeTezProcContext procCtx)
}
}
- if (semijoins.size() > 0) {
- for (ReduceSinkOperator rs : semijoins.keySet()) {
- if (LOG.isDebugEnabled()) {
- LOG.debug("Semijoin optimization with parallel edge to map join.
Removing semijoin "
- + OperatorUtils.getOpNamePretty(rs) + " - " +
OperatorUtils.getOpNamePretty(semijoins.get(rs)));
+ if
(!procCtx.conf.getBoolVar(ConfVars.TEZ_DYNAMIC_SEMIJOIN_REDUCTION_FOR_MAPJOIN))
{
+ if (semijoins.size() > 0) {
Review comment:
Hey Jesus, SJ removal and MJ probedecode are independent from my point of
view, and thats what I was trying to achieve here -- when
TEZ_DYNAMIC_SEMIJOIN_REDUCTION_FOR_MAPJOIN is not enabled SJ removal is
triggered (similar to existing code) and when HIVE_OPTIMIZE_SCAN_PROBEDECODE is
enabled we do the extra the MJ to TS selection.
I am not sure there is a case where these two optimizations could affect
each other (?) but currently they are completely independent.
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Issue Time Tracking
-------------------
Worklog Id: (was: 419356)
Time Spent: 2.5h (was: 2h 20m)
> 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,
> HIVE-23006.03.patch
>
> Time Spent: 2.5h
> 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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