Redb slasher backend impl

[eserilev]

Issue Addressed

#4424

Proposed Changes

add redb implementation to the slasher backend

Additional Info

[eserilev]

hi @michaelsproul

so I got all the slasher test cases to pass for the redb impl EXCEPT surrounds_existing_multi_vals_single_chunk. This test just hangs and never completes. I get a log message saying "test has been running for more than 60 seconds". Not sure whats going on there, will need to spend more time figuring that part out. In general though, everything else seems to be working

The code I wrote probably has a lot of room for improvement. I'm still sort of new to Rust and am having lots of fun with the borrow checker :). In general theres a few things I wanted to mention:

• unlike lmdb and mdbx, redb has a concpt of database tables. so with this redb impl, instead of spinning up 9 separate databases, I created one database and 9 tables.
• For now I'm opening all the tables in "write" mode. This probably needs to change for functions like get, next_key etc. tables are opened in read mode when relevant
• Theres some general cleanup that needs to happen here. the impl of Database is mostly commented out. I have some functions there I'd like to use, but they dont play nice with the borrow checker. I need to spend some time figuring this out. Once this is resolved the code should be much cleaner
• theres a single panic! I need to remove. Theres also a small snippit of useless code there that needs to be changed
• Do we really need a separate commit function? As of now I've included the database commit directly in all of the relevant write functions.

If you get the chance, I could use a review of my changes up to this point. It would be great to get some general feedback so that I can understand if my implementation is at least trending in the right direction

[eserilev]

ready for a review

[michaelsproul]

do we definitely need to join the BASE_DB here? I think the caller takes care of that already when constructing the config.database_path

[michaelsproul]

I just pushed a minor optimisation that avoids collecting into an intermediate Vec: 6b0a81f

[michaelsproul]

Also just back-merged unstable so the version reads 5.2

[michaelsproul]

Just pushed one change to tidy up the DB filename, which we would have trouble changing later.

[michaelsproul]

@Mergifyio queue

[mergify]

queue

✅ The pull request has been merged automatically

The pull request has been merged automatically at 70bcba1