Add the support of the restore command

[git-hulk]

This PR will close #1648 which supports the restore command for making Redis migration tools happy. To achieve this feature, we need to implement all encoding types now supported by Redis from 2.x to 7.x which includes:

• All kinds of data objects like String/List/Set/Hash/Sorted Set
• Binary encoding types: ZipMap/ZipList/IntSet/ListPack

For test cases, I have dumped value for Redis according to encoding types and confirmed it works well with the RedisShake migration tool. Another thing to be noticed, we haven't supported the stream and module type yet, because our stream type is partially implemented, so we can go back to support it after all commands are supported.

[git-hulk]

PR is ready to be reviewed, but I need some time to add test cases for all encoding types.

[PragmaTwice]

For compatibility testing, I think we can start a redis service in CI and do some mutual en/decoding? e.g. KvrocksDecode(RedisEncode(x)) = x or RedisDecode(KvrocksEncode(y)) = y

[git-hulk]

For compatibility testing, I think we can start a redis service in CI and do some mutual en/decoding? e.g. KvrocksDecode(RedisEncode(x)) = x or RedisDecode(KvrocksEncode(y)) = y

Aha, my test case values are dumped from the Redis, it should be difficult since those encoding types are located in many Redis versions, for example, the zip map exists in Redis 2.x.

[git-hulk]

Sorry for the big PR but the good news is it only affects the restore command itself :)

[torwig]

@git-hulk Yeah, a massive PR! But I believe we will handle it :)

[git-hulk]

@git-hulk Yeah, a massive PR! But I believe we will handle it :)

Thank you! That's a bit hard to review since most of them are Redis encoding-related implementations. All test values are dumped from the Redis from Redis 2.6(dump command was supported from this version), and now test cases can cover all sorts of encoding types to guarantee it works.

[git-hulk]

I have tested the RedisShake to migrate Redis data into Kvrocks and it works well now.

[enjoy-binbin]

great jobs. i added some minor comments.
did not review the RDB part since i'm not familiar with it, i am not able th give the advice.

[git-hulk]

Thanks all, I will merge this PR and can submit an issue to followup if you found any issues.