Very slow destructors of binary_oarchive and filtering_streambuf

From: boost.5nyej_at_[hidden]
Date: 2022-10-03 17:57:24

Hello, I just posted a question on StackOverflow, but I realised that this mailing list might be a better place.

The link to the question is: https://stackoverflow.com/questions/73938656/very-slow-destructors-of-binary-oarchive-and-filtering-streambuf

Tl;dr;
I have a code that serializes a big object by using binary_oarchive and filtering_bufstream. The writing on its own takes around 28 minutes, but the deconstructors of the mentioned classes take 37 and 36 minutes, respectively.

It is very strange to me that they would take so much time to run, as the first deconstructor adds only 2KiB of data, and the second deconstructor doesn't change anything.

Could you help me find the root cause of those execution times?