Sunday, February 10, 2013

PHP caching: shm vs. apc vs. memcache vs. mysql vs. file cache (update: fill apc from cron)

Lessons learned:
  • shm/apc are 32-60 times faster than memcached or mysql
  • shm/apc are 2 times faster than php file cache with apc
  • php file cache with apc is 15-24 times faster than memcached or mysql
  • mysql is 2 times faster than memcached when storing more than 400 bytes
  • memcached is 2 times faster than mysql when storing less than 400 bytes
  • php file cache with apc is 2-3 times faster than normal file cache
  • php file cache without apc is 8 times slower than normal file cache

Wednesday, February 6, 2013

Next generation refactoring with syntactical grep and patch from pfff

Refactoring of PHP methods is often difficult:
  • syntax errors or non-existing methods are only detected during runtime
  • wrong method calls or uninitialized variables are only detected during runtime
  • wrong order of parameters often remains undetected
  • not enough unit tests to validate the changes
  • not many resources for refactoring (time + money)
We can solve most of these issues by using a few tools for syntactic analysis.

Friday, February 1, 2013

Analyze log files from several servers in real-time (update: whois, firewall)

First, we setup a machine to analyze the logs:

# install missing packages (e.g. with Ubuntu 12.10)
apt-get install netcat logtop

# create a ramdisk with 1GB for storing the logs
mkdir /ramdisk
mount -t tmpfs -o nosuid,noexec,noatime,size=1G none /ramdisk

# receive logs on port 8080
ncat --ssl -l -k 8080 > /ramdisk/access.log
# open second terminal
tail -f /ramdisk/access.log | logtop

# clean up the ramdisk from time to time
echo >/ramdisk/access.log

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