Date: Mon, 31 Dec 2018 12:29:22 -0500
From: Noah Misch <noah@leadboat.com>
To: pgsql-hackers@postgresql.org
Subject: pg_regress: promptly detect failed postmaster startup
Message-ID: <20181231172922.GA199150@gust.leadboat.com>
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When "make check TEMP_CONFIG=<(echo break_me=on)" spawns a postmaster that
fails startup, we detect that with "pg_regress: postmaster did not respond
within 60 seconds".  pg_regress has a kill(postmaster_pid, 0) intended to
detect this case faster.  Since kill(ZOMBIE-PID, 0) succeeds[1], that test is
ineffective.  The fix, attached, is to instead test waitpid(), like pg_ctl's
wait_for_postmaster() does.

[1] Search for "zombie" in
http://pubs.opengroup.org/onlinepubs/9699919799/functions/kill.html

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 filename="pg_regress-dead-postmaster-v1.patch"

diff --git a/src/test/regress/pg_regress.c b/src/test/regress/pg_regress.c
index 63fe689..2c46941 100644
--- a/src/test/regress/pg_regress.c
+++ b/src/test/regress/pg_regress.c
@@ -2414,7 +2414,7 @@ regression_main(int argc, char *argv[], init_function ifunc, test_function tfunc
 			 * Fail immediately if postmaster has exited
 			 */
 #ifndef WIN32
-			if (kill(postmaster_pid, 0) != 0)
+			if (waitpid(postmaster_pid, NULL, WNOHANG) == postmaster_pid)
 #else
 			if (WaitForSingleObject(postmaster_pid, 0) == WAIT_OBJECT_0)
 #endif

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