architecture change: queue now always has at least one worker thread

...if not running in direct mode. Previous versions could run without
any active workers. This simplifies the code at a very small expense.
See v5 compatibility note document for more in-depth discussion.

1 files changed, 11 insertions, 0 deletions

diff --git a/doc/v5compatibility.html b/doc/v5compatibility.html
index 24fcbd25..6d60062f 100644
--- a/doc/v5compatibility.html
+++ b/doc/v5compatibility.html
@@ -16,4 +16,15 @@ available. This processing was redundant and had a lot a drawbacks.
 For details, please see the
 <a href="v4compatibility.html">rsyslog v4 compatibility notes</a> which elaborate
 on the reasons and the (few) things you may need to change.
+<h2>Queue Worker Thread Shutdown</h2>
+<p>Previous rsyslog versions had the capability to &quot;run&quot; on zero queue worker
+if no work was required. This was done to save a very limited number of resources. However,
+it came at the price of great complexity. In v5, we have decided to let a minium of one
+worker run all the time. The additional resource consumption is probably not noticable at
+all, however, this enabled us to do some important code cleanups, resulting in faster
+and more reliable code (complex code is hard to maintain and error-prone). From the
+regular user's point of view, this change should be barely noticable. I am including the
+note for expert users, who will notice it in rsyslog debug output and other analysis tools.
+So it is no error if each queue in non-direct mode now always runs at least one worker
+thread.
 </body></html>