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https://issues.apache.org/jira/browse/FLINK-14845?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16978343#comment-16978343
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Jingsong Lee commented on FLINK-14845:
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> doesn't Blink work on batches of records? Couldn't the (columnar?)
> compression be performed there? Either via some mapping operator or on record
> serialisation/deserialisation layer?
Current Blink work on BaseRow which means work on per record, In table/sql
layer, we can not select the sub result partition, so these row->ColumnarBatch
and compression things should do after sub partition selected. So we must
provide some special batch serialization and related compression interface to
support columnar batch and its compression for table/sql layer.
> Introduce data compression to blocking shuffle.
> -----------------------------------------------
>
> Key: FLINK-14845
> URL: https://issues.apache.org/jira/browse/FLINK-14845
> Project: Flink
> Issue Type: Sub-task
> Components: Runtime / Network
> Reporter: Yingjie Cao
> Assignee: Yingjie Cao
> Priority: Major
>
> Currently, blocking shuffle writer writes raw output data to disk without
> compression. For IO bounded scenario, this can be optimized by compressing
> the output data. It is better to introduce a compression mechanism and offer
> users a config option to let the user decide whether to compress the shuffle
> data. Actually, we hava implemented compression in our inner Flink version
> and here are some key points:
> 1. Where to compress/decompress?
> Compressing at upstream and decompressing at downstream.
> 2. Which thread do compress/decompress?
> Task threads do compress/decompress.
> 3. Data compression granularity.
> Per buffer.
> 4. How to handle that when data size become even bigger after compression?
> Give up compression in this case and introduce an extra flag to identify if
> the data was compressed, that is, the output may be a mixture of compressed
> and uncompressed data.
>
> We'd like to introduce blocking shuffle data compression to Flink if there
> are interests.
>
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