MySQL Bugs: #43595: signals are being masked/lost/forgotten when using event threads

Bug #43595	signals are being masked/lost/forgotten when using event threads
Submitted:	12 Mar 2009 13:15	Modified:	19 Mar 2009 18:43
Reporter:	Nick Loeve (OCA)	Email Updates:
Status:	Can't repeat	Impact on me:	None
Category:	MySQL Proxy: Core	Severity:	S3 (Non-critical)
Version:	0.8	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
It takes a few times before a signal (SIGINT or SIGTERM) sent to the proxy is caught and acted upon.

Sometimes you may be lucky and it is caught first go. 

How to repeat:
Start the 0.8 version of proxy and send it a SIGINT.

Suggested fix:
In my branch on lp, I just stopped using libevent for signal handling and SIGINT and SIGTERM are caught reliably.

Thank you for the report.

Where did you download version 0.8?

I am developing a plugin based on the 0.8 branch at launchpad: https://code.launchpad.net/~jan-kneschke/mysql-proxy/threaded-io

Thank you for the feedback.

Which revision do you use? I ask, because this branch shows 0.7.0 for me:

$bzr info
Checkout (format: rich-root-pack)
Location:
       checkout root: .
  checkout of branch: http://bazaar.launchpad.net/%7Ejan-kneschke/mysql-proxy/threaded-io/

$./src/mysql-proxy --version
mysql-proxy 0.7.0
  glib2: 2.16.3
  libevent: 1.4.8-stable

$bzr up
Tree is up to date at revision 640.

Also, please, indicate, if you start Proxy with some options and/or there is workload on Proxy when you call kill -SIGINT: I can stop Proxy successfully from the first try.

Hmm, I was running the proxy under load with the event-threads option set to 4.

It seems that now I cannot reproduce with that branch (which although it says 0.7.0, is the start of the 0.8 series according to launchpad), where as the other day I could. Sorry for the time waster, Ill close this now.

I found the issue:

I was able to reproduce again. The difference is on the machine where I noticed we were using libevent-1.4.7, and locally I am using libevent-1.4.9.

Using the latest libevent the issue disappears. I re-opened because this will affect the minimal version a dependency. Feel free to close this bug if it is not necessary.

Thank you for the feedback.

Closed as "Can't repeat".

Minimum version of libevent required should be documented somewhere though.