Google code search used mmap and go back in the day: Regular Expression Matching with a Trigram Index or How Google Code Search Worked https://swtch.com/~rsc/

Google code search used mmap and go back in the day: Regular Expression Matching with a Trigram Index or How Google Code Search Worked https://swtch.com/~rsc/regexp/regexp4.html https://swtch.com/~rsc/regexp/regexp4.html https://github.com/google/codesearch/tree/master/index https://github.com/google/codesearch/tree/master/index I used mmap in a go project that had large (GByte) hash tables. Sidesteps any GC pauses and makes for very fast file loading.