[gdal-dev] Performance problems

[Mark Overmeer]

* Ari Jolma (ari.jolma at gmail.com) [120317 07:41]:
> This is a broader question, but maybe somebody can help.
>                                   ... Thus, when 10 students all
> made requests at the same time, all memory was used (apache logs
> have "Out of memory!" - I'm not sure where this comes from) and the
> service did not work (QGIS reacted by turning gray ad had to be
> killed).

This is a disadvantage of the "take what you want" approach of
UNIX.  When everyone starts grabbing, the IO-system gets soaked,
extreme performance degradation, and the a certain death.

> Is there a way to refuse starting a service if there are not enough
> resources? This would lead to a much nicer response than gray QGIS.

Did you try to simple reduce the number of childs for apache?  Bring it
down to two or three.

Out-of-memory can also be "out of virtual memory".  It may help to add
more swap-space (file or partition)  Problems will stay alive longer,
but it depends on the way the data is accessed whether the programs
have any run-time left or spend all their time waiting for disk.  At
least, you can monitor that... Out-of-memory errors are quite blunt.

(The students have no laptops themselves?)
-- 
CU,
               MarkOv