Slow rendering (column statistics) after migration


#1

After migrating to a new system, most parts work fine and perform as
before. But the xml template where I use column statistics performs
very bad: 8 seconds instead of 0.2 seconds on the old system. There I
use statements like: ‘xml.min_resolution(satellite.sensors.minimum
(:min_resolution))’. Database performance is good, it is the rendering
which takes a long time. When I remove the column statistics commands
from the template, performance is like on the old system.

The new system is using newer versions of the system software (new/
old): ruby 1.8.7/ruby 1.8.6, rails 2.2.2/rails 2.1.1, Linux
2.6.18-92.el5 (both), MySQL 5.0.45 (both).

Any idea what can cause such a problem?


#2

On Jan 6, 12:55 pm, Albert removed_email_address@domain.invalid wrote:

After migrating to a new system, most parts work fine and perform as
before. But the xml template where I use column statistics performs
very bad: 8 seconds instead of 0.2 seconds on the old system. There I
use statements like: ‘xml.min_resolution(satellite.sensors.minimum
(:min_resolution))’. Database performance is good, it is the rendering
which takes a long time. When I remove the column statistics commands
from the template, performance is like on the old system.

I suggest you get ruby-prof and see where the time is going.

Fred