Hi,
Le 11/07/2013 11:20, Martin Kersten a écrit :
Without insight into your benchmark queries and database schema
for the row stores, little can be said.
Sure... but I just wanted to get past the obvious problems before
going into the details.
A
typical pitfall could be to use row-based queries such as "SELECT
* FROM tableexpr", which would call
for expensive tuple reconstruction of all columns.
No, we don't. In fact, Mondrian doesn't, to be precise.
Another explanation can come from a multidimensional
index maintained in a rowstore to speedup grouping.
We did not declare any index in MonetDB. Maybe this is the problem ?
Last
but not least, it could be grouping order or
skewed data distribution.
MonetDB provides some tools to see where time goes, which may give
a hint.
http://www.monetdb.org/Documentation/Manuals/MonetDB/Profiler/Stethoscope
I will investigate and try to find out what is happening. I'll come
back with more information.
Your table sizes reported is not extreme at all.
That is what I thought... and why I'm asking, as my current results
are really not expected...
Regards,
Franck