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https://issues.apache.org/jira/browse/FLINK-30073?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17635403#comment-17635403
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Roman Khachatryan commented on FLINK-30073:
-------------------------------------------

According to the ticket (FLINK-14484), the purpose of fixed-per-slot is to cap 
memory usage by RocksDB (while at the same time having flexible memory 
distribution among tasks in a slot).
The non-strict limit issue (FLINK-15532) is a separate one and still can not be 
resolved AFAICT.

I don't think there are any design limitations here.
EmbeddedRocksDBStateBackend could simply return false from useManagedMemory() 
if fixed-per-slot > 0.

WDYT?

> Managed memory can be wasted if RocksDB memory is fixed-per-slot
> ----------------------------------------------------------------
>
>                 Key: FLINK-30073
>                 URL: https://issues.apache.org/jira/browse/FLINK-30073
>             Project: Flink
>          Issue Type: Bug
>          Components: Runtime / Task
>    Affects Versions: 1.16.0, 1.17.0, 1.15.2
>            Reporter: Roman Khachatryan
>            Priority: Major
>
> When 
> [state.backend.rocksdb.memory.fixed-per-slot|https://github.com/apache/flink/blob/ba4b182955867fedfa9891bf0bf430e92eeab41a/flink-runtime/src/main/java/org/apache/flink/runtime/util/config/memory/ManagedMemoryUtils.java#L75]
>  is set, RocksDB does not use managed memory (this option overrides the 
> 'state.backend.rocksdb.memory.managed').
> However, the runtime [doesn't take this into 
> account|https://github.com/apache/flink/blob/ba4b182955867fedfa9891bf0bf430e92eeab41a/flink-runtime/src/main/java/org/apache/flink/runtime/util/config/memory/ManagedMemoryUtils.java#L75]
>  and still reserves the managed memory according to the configured weigths.
> cc: [~yunta]



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