No request delivery notification has been received from LSAPI application, possible dead lock.

Support and Discussion Web Server
1

Hi,

I found many erroe messages “No request delivery notification has been received from LSAPI application, possible dead lock.” on the cyberpanel error log page.

Long story short, i realised if i disabled sleep(5), or reduced it in one of my php script, it went away.

So i tested it with a single php script with just 1 commend in a while loop:
sleep(10);

And I confirmed that the sleep command produced “No request delivery notification has been received from LSAPI application, possible dead lock.” message.

What could be the settings paramters that cause this, is there any way to tune the settings to prevent this error message?

Thanks
ACP

2

Forgot to mentioned, i am using:

  1. Ubuntu 18.04.2 LTS
  2. Cyberpanel 1.8 Build 4
  3. Openlite LITESPEED/1.4.47 OPEN
3

test.php for duplicating the deadlock error:

<?php // clear buffer, just trying if it will fixed the deadlock warning => it does not. /* set_time_limit(180); ini_set('output_buffering', 0); ini_set('implicit_flush', 1); ob_end_flush(); ob_start(); */ $max = 20 ; $i = 0 ; while ($i < $max) { // usleep(900000); sleep(3); // echo "test"; header("Status: 200"); ob_flush(); flush(); $i++ ; }
4

The error went away after I upgraded to latest release of cyberpanel a while ago:

Cyberpanel: 1.8 Latest Build 5
OpenLitespeed: LITESPEED/1.4.47 OPEN

Note: OpenLiteSpeed still using the same version, what fixed the problem?
Also, anything guide on settings we can tune whenever we encounter this deadlock problem?

Thanks.
ACP

5

Same Notice here: 2019-07-22 14:04:59.454004 [NOTICE] [XXX.XXX.XX.XXX:21706] No request delivery notification has been received from LSAPI application, possible dead lock.

Cyberpanel: 1.8 Latest Build 7
OpenLitespeed: LITESPEED/1.4.49 OPEN

6

Cyberpanel 1.9
When i want upgrade Prestashop 1.6.1.22 → 1.7.6.1 i have error 500 and logs look like:

2019-10-23 15:07:10.209586 [NOTICE] [MY_SERVER_IP:61542:HTTP2-3#MY_DOMAIN] No request delivery notification has been received from LSAPI application, possible dead lock.

Maybe it’s problem with app like Presta or other…

7

restart the panel openlitespeed

8

I’m experiencing the same problem with a WordPress website. Error log overloaded by “No request delivery notification has been received from LSAPI application, possible dead lock.” notice.

Any ideas how can I find the root of this issue and fix it?

9

I get these constantly from wordpress sites…I can trace some back to webcrawlers in the activity log.

Others are from the server itself which I think is the cache plugin crawler.

I have made many adjustments, but have not been able to fix them.

There is a cryptic mention of this in the 1.6.x branch (changelog) of open Litespeed which says the notifications are from php processes that take to long.

Googling the issue is pretty useless.