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https://issues.apache.org/jira/browse/HIVE-6418?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13906368#comment-13906368
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Sergey Shelukhin commented on HIVE-6418:
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Lazy deserialization-enabled table (before any activity, so no rows are
deserialized) looks like this:
|Class|Objects|Shallow Size|Retained Size|
|byte[]|1000000|49968000|49968000|
|java.lang.Object[]|2000000|48000000|121968000|
|java.util.HashMap$Entry|1000000|32000000|201968000|
|org.apache.hadoop.hive.ql.exec.persistence.LazyFlatRowContainer|1000000|32000000|105968000|
|org.apache.hadoop.hive.serde2.io.DoubleWritable|1000000|24000000|24000000|
|org.apache.hadoop.hive.ql.exec.persistence.MapJoinKey|1000000|16000000|64000000|
|java.util.HashMap$Entry[]|1|8388624|210356624|
|java.util.HashMap|1|48|210356672|
Savings of further 23% compared to fully eager table (at the cost of byte
copying)
> MapJoinRowContainer has large memory overhead in typical cases
> --------------------------------------------------------------
>
> Key: HIVE-6418
> URL: https://issues.apache.org/jira/browse/HIVE-6418
> Project: Hive
> Issue Type: Improvement
> Reporter: Sergey Shelukhin
> Assignee: Sergey Shelukhin
> Attachments: HIVE-6418.01.patch, HIVE-6418.02.patch,
> HIVE-6418.03.patch, HIVE-6418.WIP.patch, HIVE-6418.patch
>
>
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