Support for BF.LOAD command to handle AOF Rewrite

valkey-io / valkey-bloom

Rust based Valkey Module which provides a BloomFilter data type / APIs

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Support for BF.LOAD command to handle AOF Rewrite #8

Closed KarthikSubbarao closed 1 week ago

KarthikSubbarao commented 1 month ago

Modules can support AOF Rewrite through a Module data type callback. valkey-bloom implements a module data type callback and during AOF Rewrite, we would want to write a "BF.LOAD" command that contains the dump of the existing bloom object with all the properties and bit vector dump so that it can be recreated when the command is used later on from the AOF File.

Syntax: BF.LOAD <key-name> <dump>

This issue will implement the data type callback here (https://github.com/valkey-io/valkey-bloom/blob/unstable/src/bloom/data_type.rs#L22) and add support for a new BF.LOAD command

wuranxx commented 1 month ago

@KarthikSubbarao I'd like to contribute this feature. Is this already under development?

Is BF.LOAD the equivalent of redisbloom's BF.LOADCHUNK? Do we need to implement BF.LOAD and BF.DUMP (BF.DUMP replaces BF.SCANDUMP) at the same time? Do the two commands need to be consistent with the command names of redisbloom to ensure API compatibility?

KarthikSubbarao commented 1 month ago

@wuranxx - Thank you. This feature is not yet under development, and you can contribute it.

BF.LOAD is intended to provide similar functionality (to restore a bloom object), but it is different from BF.LOADCHUNK.

We only plan to use this during AOF Rewrite. You can take a look at the "AOF Rewrite handling" section in the ValkeyBloom RFC here
It does not load in iterations. It loads / restores a bloom object in one go.

For save (equivalent to BF.SCANDUMP), valkey-bloom provides RDB Save functionality which can be used. Alternatively, when using AOF, we will write the BF.LOAD command as mentioned above