Yes, the data type matters a lot and it can be quite challenging, especially when dealing with media files such as videos due to existing compression as media codecs are very efficient.

In your case, with the database dump being a text file, I expect the compression results to be quite impressive. However, it's also crucial to consider the similarity of the data within your database. Although I haven't worked with compression in a while, I've experienced notable success in the past by increasing the dictionary size.

Take a look at for compression algos benchmarks: https://www.mattmahoney.net/dc/text.html