On 10/01/12 13:45, Andy Seaborne wrote:
On 09/01/12 15:07, Simon Helsen wrote:
Andy, others,
I have been testing TxTDB on my end and functionally, things are looking
good. I am not able to see any immediate problems anymore. Of course,
there may still be more exotic things left, but those can probably
managed
in am minor release. However, now that it is getting good on the
functional end, I am starting to check the non-functional
characteristics,
especially speed and scalability (in terms of multiple clients). For this
I use a test suite with about 35 different queries and I compare the
performance against Jena 2.6.3/ARQ 2.8.5 and TDB 0.8.7 because that is
the
version we currently use in the release of our product.. I am comparing
these numbers then with Jena/ARQ 2.7.0 and TDB 0.9.0 (20111229) and the
transaction API. I realize this partially comparing apples to pears but
from our perspective, we need to see how the bottomline changes in terms
of query speed when we increase the number of concurrent clients.
I have detailed numbers, but before I start sharing these, I want to know
if there is anything I could/should do to tune ARQ/TxTDB in terms of
performance. For instance, I wonder if there are still a whole range of
checks active which I can/should turn off now that we are functionally
more sound. For completeness, I should add that we don't use any
optimization (i.e. we run with none.opt )
thanks
Simon
Simon,
Figure would be good. If you use TDB without touching the transaction
system then it should be the same as before (with the obvious chances of
unintended changes). Have you run this way?
Just creating a transaction, especially one that allows write is a cost
and if the granularity is small then it's going to make a big
difference. (This is one reason there isn't an "autocommit" mode - it
only seems to end in trouble one way or another). Read transactions are
cheaper but not free.
In terms of tuning, TDB 0.9 needs more heap as the transaction
intermediate state is in-RAM , with no proper spill-to-disk yet.
There shouldn't be the internal consistency checking enabled. Hmm -
better check yet again!
Andy
Simon,
Could you profile the tests and pass on the results? Any testing code
left should show as hotspots.
Andy
