From 922f52d80354a8baa4d4fc939a8417ad8de33fca Mon Sep 17 00:00:00 2001 From: Emily Lamancusa Date: Wed, 9 Aug 2023 12:29:35 -0400 Subject: [PATCH] Bug 34470: Initialize random seed after spawning a child worker process When background_jobs_worker.pl spawns a new child process, it needs to explicitly reinitialize the random seed - otherwise each child process will inherit the same random seed from the parent process, and any randomization will produce identical results each time. This patch adds a call to srand immediately after the fork to reinitialize the seed. Note that child processes should not call srand with no parameter anywhere else, as the Perl documentation indicates that srand should not be called with no parameter more than once per process. To test: 1. Apply the logging patch only 2. Set system preferences: a. RealTimeHoldsQueue -> Enable b. RandomizeHoldsQueueWeight -> in random order 3. Watch the logs for the staff interface in ktd: ktd --shell koha-intra-err 4. Place a hold. Note that the logs display the branch list before and after it is randomized. 5. Place some more holds. Note that the branch order after randomization is identical each time. 6. Apply both patches and restart_all 7. Repeat steps 3-5. -> Note that the branch order before randomization hasn't changed -> Note that the branch order after randomization is now different each time. Signed-off-by: Nick Clemens --- misc/workers/background_jobs_worker.pl | 2 ++ 1 file changed, 2 insertions(+) diff --git a/misc/workers/background_jobs_worker.pl b/misc/workers/background_jobs_worker.pl index c54610458f..7d2c4f3876 100755 --- a/misc/workers/background_jobs_worker.pl +++ b/misc/workers/background_jobs_worker.pl @@ -135,6 +135,7 @@ while (1) { } $pm->start and next; + srand(); # ensure each child process begins with a new seed process_job( $job, $args ); $pm->finish; @@ -152,6 +153,7 @@ while (1) { next unless $args; $pm->start and next; + srand(); # ensure each child process begins with a new seed process_job( $job, { job_id => $job->id, %$args } ); $pm->finish; -- 2.30.2