From f2857af485a00ab5dbfa2c83af9d83afe4378239 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Fri, 6 Jan 2023 10:09:02 +1300 Subject: [PATCH] Use unnamed POSIX semaphores on Cygwin. Testing on CI showed that Cygwin's semctl() can fail with EAGAIN (possibly due to resource limits in cygserver that could be tuned, not examined). Switch to so-called POSIX semaphores instead, which don't seem to fail in that way (possibly due to a more direct implementation using Windows semaphore primitives instead of talking to cygserver, based on a cursory glance at the source). Other known problems still prevent PostgreSQL from running on Cygwin without random crashes, but this rarer problem was noticed while testing. Discussion: https://postgr.es/m/CA%2BhUKG%2BQ6DU4Ov9LrvUyDcF3oHS4KMRVSKmVGaeePq-kOyG9gA%40mail.gmail.com --- meson.build | 1 + src/template/cygwin | 5 +++++ 2 files changed, 6 insertions(+) diff --git a/meson.build b/meson.build index 8999170b4d..45fb9dd616 100644 --- a/meson.build +++ b/meson.build @@ -211,6 +211,7 @@ if host_system == 'aix' memset_loop_limit = 0 elif host_system == 'cygwin' + sema_kind = 'unnamed_posix' cppflags += '-D_GNU_SOURCE' dlsuffix = '.dll' mod_link_args_fmt = ['@0@'] diff --git a/src/template/cygwin b/src/template/cygwin index 3f42e2f8b6..4a03707a85 100644 --- a/src/template/cygwin +++ b/src/template/cygwin @@ -1,5 +1,10 @@ # src/template/cygwin +# Prefer unnamed POSIX semaphores if available, unless user overrides choice +if test x"$PREFERRED_SEMAPHORES" = x"" ; then + PREFERRED_SEMAPHORES=UNNAMED_POSIX +fi + SRCH_LIB="/usr/local/lib" # This is required for ppoll(2), and perhaps other things