[Feature request] compression/decompression in lua scripts

[halaei]

I couldn't find any command available in lua script to decompress strings compressed via popular compression libraries like zlib. It will be great if redis lua interpreter loads a zlib library by default.

Also any practical advice regarding decompressing string in lua scripts evaled by Redis is appreciated.

[itamarhaber]

Hello @halaei.

I couldn't find...

That's because there isn't, but you've learned that the hard way.

It will be great if redis lua interpreter loads a zlib library by default.

Superficially, that could be a good a idea. However, do you really want Redis to spend its time (currently, Lua scripts block the main server thread) on compression and decompression? If Redis a Ferrari, that's like using it to drive to the grocery store :)

That said, while Redis itself doesn't do compression, Redis modules can! I'm not aware of a zlib module (although it should be fairly easy to put one together), but here's something that does a fairly sophisticated zstd (IIRC threaded): https://github.com/chadnickbok/redis-zstd-module

[halaei]

About redis spending time on decompression; I want that if the time complexity is linear with respect to the string size. If I am not making a mistake, the time for that is actually linear, so why not? For my use-case I actually don't need compression inside lua script.
Thanks for the provided link.