ACEDB main memory requirements

Danielle et Jean Thierry-Mieg mieg at kaa.crbm.cnrs-mop.fr
Sat Jun 24 09:58:42 EST 1995


ACEDB does NOT loads the full database in ram
The amount of required memory is:
size of cache 1 (configurable but at elast as big as the biggest
object in the database, typically 2 or 4 Megs)
size of cache 2 (typically 2 to 4 megs, however from 2-0 to 3-7
there was a wrong aasumption in the cache management which caused the
cache 2 to grow larger in some cases. This is fixed in 4.0)
size of the dictionaries: around 40 bytes per object, reduced to around 20
in 4.0 (however this is the theory and measurments in aquilla seem to indicate
that the gain is not large, so there may be a bug in the newer system)
Typically, acedb handles around 100k objs, hence this amounts to another 4Megs

add to that the code and stack space and you end up with an image size between
12 and 20 Megs, a far cry from the full database size.

In IGD however, we have around 1M-objs implying over 50 M of image in 3.5
hopefully closer to 30 in 4.0

If we hope to go to 10 or 100 Million objects, we will have to redesign the
system at this place, and this is part of the //GD project with possibly
a prototype around summer 96.


If you run several session on one machine, you easilly run into problems.
The non-graphic client server system works well by nozw but the
graphic client still needs development work (I may work on it this summer)

Jean




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