> It's a db dump, does that matter a lot? This is like the only thing that ever matters in compression. I can easily produce 1GB of data that is nearly incompr

> It's a db dump, does that matter a lot? This is like the only thing that ever matters in compression. I can easily produce 1GB of data that is nearly incompressible next to 1GB of data that can be reduced by a lousy but fast algorithm that just prints '1GB of \x00'. There are statistical tools that can apparently give you an estimate how random your data is, but I know next to nothing of them. A DB dump is probably (but not necessarily) in human-readable SQL so should compress similar to any novel you can download from project Gutenberg. For some special use cases (and of course, most conspicuously, AV media data streams), specialized compression algorithms should be able to make a difference, but I doubt the generic tools we have can be surpassed by much for human-readable text when used with the most aggressive settings (i.e. small size at the cost of time and maybe memory consumption). This is what they were optimized for in the first place. Trying to gzip a PNG image is a fruitless endeavor.