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https://issues.apache.org/jira/browse/HIVE-21391?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Prasanth Jayachandran reassigned HIVE-21391:
--------------------------------------------
Assignee: Prasanth Jayachandran
> LLAP: Pool of column vector buffers can cause memory pressure
> -------------------------------------------------------------
>
> Key: HIVE-21391
> URL: https://issues.apache.org/jira/browse/HIVE-21391
> Project: Hive
> Issue Type: Bug
> Components: llap
> Affects Versions: 4.0.0, 3.2.0
> Reporter: Prasanth Jayachandran
> Assignee: Prasanth Jayachandran
> Priority: Major
>
> Where there are too many columns (in the order of 100s), with decimal, string
> types the column vector pool of buffers created here
> [https://github.com/apache/hive/blob/master/llap-server/src/java/org/apache/hadoop/hive/llap/io/decode/EncodedDataConsumer.java#L59]
> can cause memory pressure.
> Example:
> 128 (poolSize) * 300 (numCols) * 1024 (batchSize) * 80 (decimalSize) ~= 3GB
> The pool size keeps increasing when there is slow consumer but fast llap io
> (SSDs) leading to GC pressure when all LLAP io threads read splits from same
> table.
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