Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : Apache process using 100% of CPU

[k2host]

Multiple times daily there is an apache process that hangs and uses 100% of the CPU (it's a dual xeon). It is apache and not PHP, so I don't know how to identify what's causing the problem. Other apache processes come and go just fine while that one process continues to hang.

If I simply restart apache, everything will run fine.

How do I determine what's causing this apache process to hang?

[Paco]

It's php for sure, in apache scripts.

Try to install Zend or eaccelerator and optimize the my.cnf (mysql) configuration file.

[k2host]

Paco-

Mysql is well optimized, and being that the only site on the server is the site I myself coded, I'm confident in saying there's no PHP bug or issue causing the hang.

Rather then just throwing a blanket over this, I want to figure out exactly what is causing the process to hang.

Anyone else know how to identify this?

Thanks.

[submenu]

Never seen it before, try recompiling and see if that helps

[Doctorbob]

Originally Posted by k2host

Multiple times daily there is an apache process that hangs and uses 100% of the CPU (it's a dual xeon). It is apache and not PHP, so I don't know how to identify what's causing the problem. Other apache processes come and go just fine while that one process continues to hang.

If I simply restart apache, everything will run fine.

How do I determine what's causing this apache process to hang?

find out the pid of the apache process and and do an strace (strace -p pid). You should able to find something interesting.

[k2host]

Okay, it happened again and I strace'd it this time:

munmap(0x6086000, 4993024)              = 0
fcntl64(16, F_SETFL, O_RDWR|O_NONBLOCK) = 0
read(16, 0x97c2580, 8192)               = -1 EAGAIN (Resource temporarily unavailable)
fcntl64(16, F_SETFL, O_RDWR)            = 0
write(16, "f\0\0\0\3select index_id, index_name"..., 106) = 106
read(16, "\233\0\0\1", 4)               = 4
read(16, "\377(\4#42000You have an error in yo"..., 155) = 155
mmap2(NULL, 4993024, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x6086000
munmap(0x560e000, 4993024)              = 0
fcntl64(16, F_SETFL, O_RDWR|O_NONBLOCK) = 0
read(16, 0x97c2580, 8192)               = -1 EAGAIN (Resource temporarily unavailable)
fcntl64(16, F_SETFL, O_RDWR)            = 0
write(16, "f\0\0\0\3select index_id, index_name"..., 106) = 106
read(16, "\233\0\0\1", 4)               = 4
read(16, "\377(\4#42000You have an error in yo"..., 155) = 155
mmap2(NULL, 4993024, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x560e000

Now, I can decipher that there appears to be an SQL error and a response of "Resource temporarily unavailable".. But I can't identify what exactly is causing the problem still. The site is still operating just fine with no sql errors when browsing it.

Any ideas?