What version of regex are you using?

1.9.5

Describe the bug at a high level.

I compiled a regex with a lot of literals as alternatives (~700KiB) and it consumed way too much memory (256MiB).

What are the steps to reproduce the behavior?

Prepare a text file with content like abc|def|text|... but about 700KiB long and ~64K |s (it could be generated from a dict file).

fn main() { let s = std::fs::read_to_string("file").unwrap(); let r = regex::Regex::new(&s); std::thread::sleep(std::time::Duration::from_secs(100)); drop(r); }

And then look at the process's memory usage.

What is the actual behavior?

It took up about 256MiB memory. Python only used 31MiB memory.

What is the expected behavior?

I expect it to use less memory than Python, not a lot more.