Extreme slow performance after changing machine ip

[tjebbeke]

From my pc this request isn't slow. You can send me a PM with more information about your server.

[skurudo]

IP-change does not affect performance.
You're sure, problem not in host machine?

[CGeorges]

http://screenshot.vodoosolutions.com/20 ... 5_1321.png

The server has 12GB Ram, MySQL uses InnoDb and has 6GB of ram dedicated.

PHP 5.4.41,
5.5.43-log MySQL Community Server (GPL) by Remi
Apache/2.2.15 (Unix)
nginx/1.8.0

Running the same queries in phpmyadmin run in a matter of ms, while the app (it doesn't do any processing except retrieving from DB and converting 9 results in JSON) you can see in the screenshot above takes 1 minute to complete.

[tjebbeke]

http://screenshot.vodoosolutions.com/20 ... 5_1321.png

The server has 12GB Ram, MySQL uses InnoDb and has 6GB of ram dedicated.

PHP 5.4.41,
5.5.43-log MySQL Community Server (GPL) by Remi
Apache/2.2.15 (Unix)
nginx/1.8.0

Running the same queries in phpmyadmin run in a matter of ms, while the app (it doesn't do any processing except retrieving from DB and converting 9 results in JSON) you can see in the screenshot above takes 1 minute to complete.

Is it just this request that is slow? Or is everything slow?

Can you provide the link so we can look it's not a local problem. (maybe in PM)

[CGeorges]

Is it just this request that is slow? Or is everything slow?

Can you provide the link so we can look it's not a local problem. (maybe in PM)

That and a few other pages that are more query intensive, although I added timers in the code and the results are in microseconds:

0.0028798580169678 0.0036330223083496 0.0015079975128174

[skurudo]

0.0028798580169678 0.0036330223083496 0.0015079975128174

It's pretty fast, what do you think?

[CGeorges]

It is. But the browser receives the response in one minute.

[CGeorges]

I'm thinking that maybe httpd or php stalls the response because of buffer being larger. I'm not sure, I'm really out of ideas of how to fix this or on to what to look into next.

[CGeorges]

Running strace shows that httpd hangs a lot for a second, but multiple times:
7013 1.001157 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000063 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 0.111947 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000059 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 1.001156 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000065 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 1.001191 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000065 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 0.112206 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000061 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 1.001131 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000050 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 1.001178 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000053 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 0.110492 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000061 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 1.001123 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000061 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 0.829601 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000062 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 0.110629 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000062 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 1.001115 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000061 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 1.001167 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000074 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 0.110453 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0
7013 0.000061 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
7013 1.001122 wait4(-1, 0x7fffed2d7b6c, WNOHANG|WSTOPPED, NULL) = 0

[CGeorges]

Turns out httpd hanged because it was trying to connect to MySQL through ipv6 even if my script stated to use ipv4. I disabled ipv6 on the server and the issue had dissipated.