Please Offer SQL DDL to Clean Up the Cache On-Demand

[xiaobingxia-at]

Feature request

Is your feature request related to a problem? Please describe. It's great to see that the latest version of Starrocks can run a SQL statement to pre-warm up the cache. But because of security reason, we don't want to leave any footprint of data at anywhere, unless it is encrypted. Data at cache is not encrypted, so we want to remove the cache from memory on demand.

Describe the solution you'd like Please offer a SQL solution like, "CLEAR CACHE FOR {TABLE XXX}", so user can execute and clear the cache.

Describe alternatives you've considered

Additional context

[wangsimo0]

Hi xiaobingxia, thanks for your advice! just want to fully understand your requirement, how is your data encrypted? are you using hive or iceberg table and encrypted orc or something? I just curious of how the whole process is

[xiaobingxia-at]

So we want all data persisted on disk / s3 to be encrypted. But we also want to leverage the caching. So the process here is:

1. We pre-warm up the cache
2. We do queries towards cache (unencrypted) + tables on s3 (encrypted)
3. We clear the cache. We can use the cache data without being encrypted, we just need to clean it on time.

[wangsimo0]

I'm not quite understand. if you are using sr's data cache, it should only cache the original data, which in your case is encrypted.

[xiaobingxia-at]

To clarify, we have SR persist data on S3 bucket. And then we apply the s3 server side encryption: https://docs.aws.amazon.com/AmazonS3/latest/userguide/serv-side-encryption.html , which means, data on s3 is encrypted by S3. When any client like SR writes data to S3, S3 will encrypt data first, when SR fetching data from S3, S3 will decrypt data first and then return the data to the SR. So SR will get the decrypted data.

[wangsimo0]

thanks for your explanation! In this case starrocks need to provide a evict cache SQL API. This is a good suggestion.