[Subtask] Setting buffer time for deletion operations to prevent accidental deletion, etc.

[yuqi1129]

Describe the subtask

After #305 & #306, we started supporting true nested deletion in graviton. This is unsafe, so we must establish a method to recover data before physically deleting it in case of accidental deletion.

A good choice is to set a buffer time before actual deletion. Users have the option to undo the deletion operation within a certain time frame.

Parent issue

#294

[yuqi1129]

We may need to do the following things.

• Mark the entity and its related sub-entities as deleted and can't be accessed.
• Set a buffer time, for example, two days for them.
• Start a daemon thread to periodically delete entities marked as deleted.
• Offer ways to make entities marked as deleted visible again.

[yuqi1129]

Possible solutions for these problems.

Mark the entity and its related sub-entities as deleted and can't be accessed.

1. Add a new key-value pair that indicates the entities and their sub-entities have been deleted. The key can share the same prefix as the key that represents deleted entities.
2. Add a property that holds deletion information for an entity. For example, introducing a field named 'valid' in CatalogEntity, if it's false, then that means the entity has been marked as deleted. This option is straightforward to implement.
3. Set multiple free bytes before the serialized byte array of entity to hold deletion information. It's similar to the second one.

I prefer the first option, while the second one can also be considered. What's your opinion? @jerryshao

[jerryshao]

Is it already done? @yuqi1129

[yuqi1129]

Yes, it was completed by #782.

[yuqi1129]

Close