[OSM-dev] FYI: performance impact of mysql_read_buffer for osmosis

[Harald Kleiner]

Hi!

If you (like me) have bought plenty of extra RAM, then optimized your 
my.cnf file to donate your RAM to MySQL (until you didn't know which 
settings you modified) and finally ended up with osmosis taking one our 
for a task that took only two minutes befor the optimisation, this info 
is for you:

Don't set the config parameters read_buffer_size and 
read_rnd_buffer_size too high! Default value is around 128KiloBytes. 
Setting them to 128MegaBytes will result in a performance degradation of 
approximately a factor 30.

Now I set the values back to 1MegaByte and stopped "optimizing"...

cheers!
Harald