[FLINK-25794][sql-runtime] Clean cache after memory segments in it after they are released to MemoryManager

[FangYongs]

What is the purpose of the change

This pr aims to clean cache in LazyMemorySegmentPool after memory segments in it are released to MemoryManager

Verifying this change

This change added tests and can be verified as follows:

• *Added test ResettableExternalBufferTest.testSegmentPoolCleanCache that validates the cache is cleared in LazyMemorySegmentPool.cleanCache

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes / no) no
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no) no
• The serializers: (yes / no / don't know) no
• The runtime per-record code paths (performance sensitive): (yes / no / don't know) no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (yes / no / don't know) no
• The S3 file system connector: (yes / no / don't know) no

Documentation

• Does this pull request introduce a new feature? (yes / no) no
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

[FangYongs]

Hello @KarmaGYZ @JingsongLi , could you help to review this issue when you're free?

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Automated Checks

Last check on commit 0b17412 (Tue Jan 25 02:35:41 UTC 2022)

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CI report:

• 4d6ae31 Azure: FAILURE

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[JingsongLi]

Hi @zjureel I replied you in JIRA.

[FangYongs]

Thanks @JingsongLi , I think I miss the operations in MemoryManager :(
And another issue is in BinaryHashTableTest.testBinaryHashBucketAreaNotEnoughMem, there's no table.free after table.close, I think it should be and it causes memory leaks in my cache memory manager. What do you think?

[JingsongLi]

Thanks @JingsongLi , I think I miss the operations in MemoryManager :( And another issue is in BinaryHashTableTest.testBinaryHashBucketAreaNotEnoughMem, there's no table.free after table.close, I think it should be and it causes memory leaks in my cache memory manager. What do you think?

I don't know, it seems that area.freeMemory() will release memory?

[FangYongs]

No, the 'area.freeMemory' will call LazyMemorySegmentPool.returnPage and return the allocated MemorySegment to LazyMemorySegmentPool.cachePages only, won't free them to MemoryManager