[Feature] Doris FileCache memory info vs disk info consistency check

[freemandealer]

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Description

Occasionally, we found that there have been cases of disk cache data escaping from the management of Doris file cache, causing disk space leaks. To make it easier for debugging, we need a checking tool that compares the contents in the Doris file cache memory management structure with the current disk contents to identify the differences between the two (which are potential problematic data).

To better understand how file cache works, please refer to: https://doris.apache.org/zh-CN/docs/dev/compute-storage-decoupled/file-cache/ and https://www.bilibili.com/video/BV1ath9eGEqL

Basic Ideas

Coz the cache is changing rapidly, we should freeze the cache (via lock) to get a snapshot of current status.

Then parse the status to get which data should be cached.

And scan the disk (also during the freeze) to see which data indeed exists.

Finally compare the above two and print the diff in logs.

Implementation Tips

We could use Restful API to trigger the check. FYI, check be/src/http/action/file_cache_action.cpp for more details of Restful API support in Doris.

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Related issues

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• Yes I am willing to submit a PR!

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