Win32 API FindFirstFile and FindNextFile performance vs command line

Question

We have encountered an unexpected performance issue when traversing directories looking for files using a wildcard pattern.

We have 180 folders each containing 10,00

Answer 1

In my tests using FindFirstFileEx with FindExInfoBasic and FIND_FIRST_EX_LARGE_FETCH is much faster than the plain FindFirstFile.

Scanning 20 folders with ~300,000 files took 661 seconds with FindFirstFile and 11 seconds with FindFirstFileEx. Subsequent calls to the same folders took less than a second.

HANDLE h=FindFirstFileEx(search.c_str(), FindExInfoBasic, &data, FindExSearchNameMatch, NULL, FIND_FIRST_EX_LARGE_FETCH);