[Qgis-developer] Approximate reprojection for vectors

Martin Dobias wonder.sk at gmail.com
Tue Oct 4 11:53:19 EDT 2011

On Mon, Oct 3, 2011 at 3:22 AM, Marco Hugentobler
<marco.hugentobler at sourcepole.ch> wrote:
>> the time spent within postgres provider while waiting for server to
>> return the features may not be considered.
> That might be a valid point. Is it better to use oprofile for the waiting time?

OProfile is a system-wide statistical profiler. Being system-wide
means that it profiles all applications (and kernel, too!) running on
the system. So it is able to measure time not only in qgis but also in
postgresql etc. And being statistical means that it is periodically
triggered by hardware and records samples what code is running at each
time. With enough samples you should have quite good idea what is
going on.

However I am not yet sure how to profile i/o waiting times - maybe
strace is a better tool in this regard.

Additionally there is no such nice GUI like kcachegrind for oprofile
output - although op2callgraph tool may be of some use.

> In any case, the other servers in the benchmark had to fetch the features from
> the same database. So there must be very performance critical differences in
> the other parts of the code. As you might know, QGIS didn't really win first
> price...

Is the benchmark (data + configuration) publicly available? Is it
simple to download it and run on a local machine?


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