Attachment 154339 Details for Bug 34470 – Bug 34470: Initialize random seed after spawning a child worker process

[patch] Bug 34470: Initialize random seed after spawning a child worker process

Bug-34470-Initialize-random-seed-after-spawning-a-.patch (text/plain), 2.26 KB, created by Nick Clemens (kidclamp) on 2023-08-09 18:13:16 UTC

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Creator: Nick Clemens (kidclamp)

Created: 2023-08-09 18:13:16 UTC

Size: 2.26 KB

patch

obsolete

>From 922f52d80354a8baa4d4fc939a8417ad8de33fca Mon Sep 17 00:00:00 2001
>From: Emily Lamancusa <emily.lamancusa@montgomerycountymd.gov>
>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 <nick@bywatersolutions.com>
>---
> 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

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