[gdal-dev] Performance problems
mark at overmeer.net
Sat Mar 17 04:48:45 EDT 2012
* 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
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?)
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