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https://issues.apache.org/jira/browse/HIVE-2555?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13152604#comment-13152604
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jirapos...@reviews.apache.org commented on HIVE-2555:
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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/2849/
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(Updated 2011-11-18 02:48:41.568039)
Review request for Yongqiang He, Ning Zhang and namit jain.
Changes
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In version 3 of this patch patricia-trie only worked with group by's on single
string column. Now it should work with group by's on any number of columns,
with following column types: String, int, long, byte, bool.
This isn't yet thoroughly tested, yet it worked on some sample queries.
The code added in this patch version is unnecessarily long, unfortunately to
shorten it in any decent way would require non-minor refactoring in the already
existing Hive code (basically upon designing and implementing the whole Hive
part responsible for objects/object inspector comparing/getting values etc. it
was to huge extent forgot that Java has polymorphism).
Summary
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Made HashTable in groupby plugable, a class that will supply hashtable
functionality has to implement ExternalMap interface. Currently I supplied 2 of
them: ExternalJavaHashMap and ExternalHPPCObjectObjectOpenHashMap
(ExternalJavaMap is an abstract class that will make adding Hashmaps that
implement java.util.Map interface easier). ExternalMap has some strange
methods, to allow doing various tricks that can increase efficiency.
ExternalMap could be easily made more general yet I decided it's not worth
doing that at this point (it could be if ExternalMap was also to be used by
other things than GroupByOperator).
I strongly dislike removing 10% of the hashmap in GroupByOperator.flush() since
no known to me HashMap implementation supplies efficient and nice way to do it,
maybe there is a way to do something about that flushing.
At this point the hppc jar is added in a way to "just work", if there is a more
proper way of adding jars, then I am not aware how to do it.
This addresses bug HIVE-2555.
https://issues.apache.org/jira/browse/HIVE-2555
Diffs (updated)
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trunk/build-common.xml 1202523
trunk/conf/hive-default.xml 1202523
trunk/lib/hppc-0.4.1.jar UNKNOWN
trunk/lib/patricia-trie-0.6.jar UNKNOWN
trunk/ql/build.xml 1202523
trunk/ql/src/java/org/apache/hadoop/hive/ql/exec/GroupByOperator.java 1202523
trunk/ql/src/java/org/apache/hadoop/hive/ql/exec/KeyWrapperFactory.java
1202523
trunk/ql/src/java/org/apache/hadoop/hive/ql/util/ExternalHPPCObjectObjectOpenHashMap.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/util/ExternalJavaHashMap.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/util/ExternalJavaMap.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/util/ExternalMap.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/util/ExternalPatriciaTrie.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/util/ListKeyWrapperAnalyzer.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/util/ObjectObjectExpandedOpenHashMap.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/util/PrivateInstantiator.java
PRE-CREATION
trunk/ql/src/java/org/apache/hadoop/hive/ql/util/TextKeyWrapperAnalyzer.java
PRE-CREATION
trunk/serde/src/java/org/apache/hadoop/hive/serde2/objectinspector/ListObjectsEqualComparer.java
1202523
Diff: https://reviews.apache.org/r/2849/diff
Testing
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Worked on some sample queries and passed queries_properties.q
Thanks,
Robert
> Make the hashmap in map-side group by pluggable
> -----------------------------------------------
>
> Key: HIVE-2555
> URL: https://issues.apache.org/jira/browse/HIVE-2555
> Project: Hive
> Issue Type: New Feature
> Reporter: Namit Jain
> Assignee: Robert Surówka
> Attachments: HIVE-2555.2.patch, HIVE-2555.3.patch
>
>
> There are a couple of implementations available (other than
> java.util.HashMap) - COLT, TROVE etc. to name a few.
> If the hashmap was pluggable, it would be easy to play around with different
> hash maps and tune performance.
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