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Re: [udig-devel] Memory Management in uDig?
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Carsten Ehbrecht wrote:
Hi,
as far as i know, udig has the advantage that it has not to load all
requested Features into memory.
In general we try and load *no* features into memory.
My question is: For which sources (shapefile, gml, wfs, postgis, ...)
can this advantage be used?
All of them do not load data into memory when displaying ...
- postgis, arcsde, oracle and so forth make use a "real" transaction so
they don't use any memory on editing
- shapefile, gml, and other "simple" things make use of some memory to
record what data you changed feature by feature
- wfs makes use of an in memory record of how your data was changed
(series up add / remove / update commands) so it will use a little bit
of memory the longer you edit
Are only those Features loaded into memory which are currently visible on the map?
Even the feature you currently see are not loaded into memory. You can
run udig as a viewer with very low memory requirements.
The Table View is the only exception; it loads the entire layer into
memory so you can scroll up and down in the table. That is usally fine;
but working with some 3 million feature arcsde tables recently makes me
worried ;-) If you accidentally open the table view you can quickly
change what is displayed in the top left before uDig pops memory.
Jody
