On Mon, Mar 20, 2017 at 11:47:03PM -0400, Noah Misch wrote: > "pgbench -i -s 50; pgbench -S -j2 -c16 -T900 -P5" freezes consistently on > Cygwin 2.2.1 and Cygwin 2.6.0. (I suspect most other versions are affected.) > I've pinged[1] the Cygwin bug thread with some additional detail.
The problem was cygserver thread exhaustion; cygserver needs a thread per simultaneous waiter. With "cygserver -r 40" or the equivalent config file setting, this test does not freeze. Cygwin 2.8.0 introduced a change to dynamically grow the thread count: https://cygwin.com/git/gitweb.cgi?p=newlib-cygwin.git;a=commitdiff;h=0b73dba4de3fdadde499edfbc7ca9d9a01c11487 However, Cygwin 2.8.0 introduced another source of cygserver freezes: https://cygwin.com/git/gitweb.cgi?p=newlib-cygwin.git;a=commitdiff;h=b80b2c011936f7f075b76b6e59f9e8a5ec49caa1 The 2.8.0-specific freezes have no known workaround. Cygwin 2.8.1 works, having reverted the problem commit. Do not use PostgreSQL with Cygwin 2.8.0. > If a Cygwin > buildfarm member starts using --enable-tap-tests, you may see failures in the > pgbench test suite. (lorikeet used --enable-tap-tests from 2017-03-18 to > 2017-03-20, but it failed before reaching the pgbench test suite.) Curious > that "make check" has too little concurrency to see more effects from this. I now understand the bug required eleven concurrent lock waiters, and it's plausible that "make check" doesn't experience that. The pgbench test suite uses -c5, so I expect it to be stable on almost any Cygwin. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
