There is a handful of places in the code related to dictionary
compression which calls get_units to acquire semaphore units but the
returned future is not awaited, seemingly by mistake. The result of
get_units is assigned to a variable - which is reasonable at a glance
because the semaphore units need to be assigned to a variable in order
to control their scope - but at the same time if co_await is mistakenly
omitted, like here, doing so will silence the nodiscard check of
seastar::future and, effectively, the get_units call will be nearly
useless. Unfortunately, this is an easy mistake to make.
Fix the places in the code that acquire semaphore units via get_units
but never await the future returned by it. I found them by manual code
inspection, so I hope that I didn't miss any.
Closesscylladb/scylladb#28581
7d6f734a51