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luky avatar Server

slow php (php-fpm) (long apache php waiting)

co flag
luky

I have an apache with PHP-FPM module, 8 CPU cores. Average CPU all together load is around 75% CPU mainly due MySQL see the screen.

It is actually little bit smaller load now than usually.

enter image description here

But problem is, when I open homepage the load is randomly around 1s (time to first byte i guess).

I thought it could be waiting due mysql connection etc, but it seems the extra time for waiting is the time, before the PHP gets the voice from Apache.

I made two interesting tests:

  • Simple html file (empty file with some word) takes 100ms to load.
  • Simple php file (no connection to mysql etc, just empty php file with simple echo) takes around 1s to load.

So problem is obviously with the php or apache+php combination.

Why, and how to fix it.

I tried to increase some PHP fpm settings like

pm = dynamic
pm.max_children = 5
pm.start_servers = 3
pm.min_spare_servers = 2
pm.max_spare_servers = 4
pm.max_requests = 200

Move the values from default bit up. Yes the CPU load went instantly up almost to 99% all CPUs but speed was not fixed + server was totally loaded.

What to do?

Btw from Apache mod-status i see that currently there is 25 requests per second handled (normally double though). And i dont think i should wait 1s to load empty php script with 8 CPU cores.

Server version: Apache/2.4.29
PHP7.2-fpm
MPM-Event
8vCPU, 16 GB RAM

BTW the empty php file takes also around 3-4s so not only 1s.

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djdomi avatar
za flag
djdomi
what kind of queries are you running that a MYSQLD is eating your system?
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luky avatar
co flag
luky
some anagram queries, on takes on average 0.5s some may take also 1.5s but usually around 0.5s.
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djdomi avatar
za flag
djdomi
are you using memcached? or similar for caching?
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luky avatar
co flag
luky
yes i am, and even the cache setting is so effective that 84% requests go from cache not from db. its not much visible on cpu load. maybe 10-15% smaller.
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in flag
Victor Pittol
Amigo tengo i3 + 4gb de ram y ajuste de esta forma.[enter image description here](https://i.stack.imgur.com/kG2FR.png)
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