After analyzing debug log I understand that probably only 1st user will have to wait until the new page is generated. And 100 other users requesting *same* page will be served from renamed needs-rebuild file.
But this wont solve the problem if 100 users will try to open 100 *different* pages. We will be forced to rebuilt 100 pages (half a minute) and those 100 first users will have to wait for this process.
Is there any way to rename only necessary pages to "needs-rebuild" file.
Or at least serve "needs-rebuild" file right away and schedule "needs-rebuild" file for rebuilding by renaming is to ".rebuilding-in-process" (processed by rewrite). And then when rebuilding is over, save fresh cache file and just delete ".rebuilding-in-process".
03:04:32 /features/ supercache dir: C:\inetpub\mysite.com/wp-content/cache/supercache/mysite.com/features/
03:04:32 /features/ No wp-cache file exists. Must generate a new one.
03:04:32 /features/ In WP Cache Phase 2
03:04:32 /features/ Setting up WordPress actions
03:04:32 /features/ Created output buffer
03:04:32 /features/ Rebuild file renamed to cache file temporarily: C:\inetpub\mysite.com/wp-content/cache/supercache/mysite.com/features/index.html
03:04:32 /features/ Rebuild file renamed to cache file temporarily: C:\inetpub\mysite.com/wp-content/cache/supercache/mysite.com/features/index.html.gz
03:04:32 /features/ Output buffer callback
03:04:32 /features/ Anonymous user detected. Only creating Supercache file.
03:04:32 /features/ Gzipping buffer.
03:04:32 /features/ Writing non-gzipped buffer to supercache file.
03:04:32 /features/ Writing gzipped buffer to supercache file.
03:04:32 /features/ Renamed temp supercache file to C:\inetpub\mysite.com/wp-content/cache/supercache/mysite.com/features/index.html
03:04:32 /features/ Renamed temp supercache gz file to C:\inetpub\mysite.com/wp-content/cache/supercache/mysite.com/features/index.html.gz
03:04:32 /features/ Writing gzip content headers. Sending buffer to browser
03:04:32 /features/ wp_cache_shutdown_callback: collecting meta data.
03:04:32 /features/ Did not write meta file: wp-cache-87dd271736cf4504a5ee220e329ee07c.meta *1* *0* *1*