Re: pgsql: Consistently test for in-use shared memory.

On Mon, Apr 15, 2019 at 08:08:48PM -0400, Tom Lane wrote:
> Noah Misch <noah@leadboat.com> writes:
> > Consistently test for in-use shared memory.
> 
> Hmm ... conchuela has just found another problem with this test case:
> 
> ok 2 - detected live backend via shared memory
> # Running: postgres --single -D
/home/pgbf/buildroot/HEAD/pgsql.build/src/test/recovery/tmp_check/t_017_shm_gnat_data/pgdatatemplate1
 
> ack Broken pipe: write( 16, 'SELECT 1 + 1' ) at /usr/local/lib/perl5/site_perl/IPC/Run/IO.pm line 549.
> 
> I interpret this as "the single-user backend exited before we could stuff
> 'SELECT 1 + 1' down the pipe to it, and the Perl script is not expecting
> to get a write failure there".

Perhaps I should write the 'SELECT 1 + 1' to a regular file and redirect input
from that file.