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https://issues.apache.org/jira/browse/KAFKA-12559?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17370331#comment-17370331
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Guozhang Wang commented on KAFKA-12559:
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[~msundeq] I've re-assigned the ticket for you. Please let us know when you've
been ready or have any questions blocking your progress.
> Add a top-level Streams config for bounding off-heap memory
> -----------------------------------------------------------
>
> Key: KAFKA-12559
> URL: https://issues.apache.org/jira/browse/KAFKA-12559
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Reporter: A. Sophie Blee-Goldman
> Assignee: Martin Sundeqvist
> Priority: Major
> Labels: needs-kip, newbie, newbie++
>
> At the moment we provide an example of how to bound the memory usage of
> rocskdb in the [Memory
> Management|https://kafka.apache.org/27/documentation/streams/developer-guide/memory-mgmt.html#rocksdb]
> section of the docs. This requires implementing a custom RocksDBConfigSetter
> class and setting a number of rocksdb options for relatively advanced
> concepts and configurations. It seems a fair number of users either fail to
> find this or consider it to be for more advanced use cases/users. But RocksDB
> can eat up a lot of off-heap memory and it's not uncommon for users to come
> across a {{RocksDBException: Cannot allocate memory}}
> It would probably be a much better user experience if we implemented this
> memory bound out-of-the-box and just gave users a top-level StreamsConfig to
> tune the off-heap memory given to rocksdb, like we have for on-heap cache
> memory with cache.max.bytes.buffering. More advanced users can continue to
> fine-tune their memory bounding and apply other configs with a custom config
> setter, while new or more casual users can cap on the off-heap memory without
> getting their hands dirty with rocksdb.
> I would propose to add the following top-level config:
> rocksdb.max.bytes.off.heap: medium priority, default to -1 (unbounded), valid
> values are [0, inf]
> I'd also want to consider adding a second, lower priority top-level config to
> give users a knob for adjusting how much of that total off-heap memory goes
> to the block cache + index/filter blocks, and how much of it is afforded to
> the write buffers. I'm struggling to come up with a good name for this
> config, but it would be something like
> rocksdb.memtable.to.block.cache.off.heap.memory.ratio: low priority, default
> to 0.5, valid values are [0, 1]
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