3 Oct
2008
3 Oct
'08
9:49 a.m.
On Oct 3, 2008, at 2:12 AM, Sergiu Dumitriu wrote:
Vincent Massol wrote:
I'm very positive for Derby (even though I haven't used it myself a
lot). It has made lots of progress in the past few years and it's
production ready, which is definitely NOT the case for HSQLDB.
Performances are very similar to MySQL and other DBs (see link I gave).
It supports Catalogs/Schema (AFAIK) so that it will even work with
multiwiki (which isn't the case for HSQLDB).
DB4O has always been something at the level of research for me but
then I haven't checked it out for the past 4 years so it's likely it
has evolved.
But right now Derby makes more sense for us.
I'm not sure at all (I would even say no) that Artem should work on
this since I haven't heard any request from XWiki users/customers to
use DB4O and I would prefer that Artem works on some feature that are
more requested by our users when he's done with JCR/QueryManager.
I don't have the slightest doubt that Derby is better than HSQLDB for
this use case. Now we could keep our current packaging and just add
this new one but I think we might just not have enough manpower to
maintain both so I would keep the HSQLDB one but not make it the
default so that what we release would be Derby+Jetty+ServiceWrapper.
That said all this is hypothetical for now since I want to finish the
new rendering before moving to something else so I won't be working on
this anytime soon. Of course if someone else is interested please go
ahead.
Thanks
-Vincent
Hi,
I was wondering today if we could provide a production quality XE
packaging.
Here's what would be my combo:
* Jetty 6 or 7
* Latest Derby (aka JavaDB - which is included in JDK 1.6 BTW) in
embedded mode
See
http://developers.sun.com/learning/javaoneonline/j1sessn.jsp?sessn=TS-45170…
for performance stats
* Java Service Wrapper
See http://wrapper.tanukisoftware.org/doc/english/integrate.html
The nice thing with the wrapper is that it can also monitor the JVM
and restart it if hung or not responding, in addition to restarting
the service when the machine is rebooted of course.
I'm confident that we could offer a base packaging that would work
well for relatively large usages of XE and that is still small and
all-
preconfigured.
Basically I think we could replace our current combo of Jetty 5.x +
HSQLDB with this new combo and still get the best of both worlds:
* simple packaging
* production level quality
Whereas our current standalone packaging is not production ready and
is just for getting started with XWiki.
WDYT?
For jetty we should use pom dependencies, and not binaries in our svn.
We could either use jetty-assembly, which is a bit too large, but
includes everything, or we could compose our own Jetty (which is
pretty
modular) from dependencies like jetty-start and jetty (the core), as
we
don't need support for JSP, cometd, servlet annotations, jmx and
others.
7.0 is in "prerelease" stage, is that something stable? 6.x seems to
continue making releases in parallel with 7.0, and they don't seem
to be
around minor fixes. As far as I've seen, the major feature of 7.0 is
support for the upcoming servlets 3.0 (asynchronous transfers, which
means better support for AJAX), and a better organization of the
source
tree (more maven conventional).
For switching to Derby, I'm not convinced. I don't know if you know
about PolePosition, a database benchmarking project. Some older
results
(I can't seem to find product versions on that site, or a date, but
the
HTML pages were modified a year ago) shows that HSQL (without
Hibernate)
is a clear winner, although it manages to do that because it keeps
most
of the data in memory, so data might be lost if the server is not
cleanly shutdown. Here's the page:
http://polepos.sourceforge.net/results/html/index.html
Some things to notice:
- Hibernate adds serious overhead.
- When using hibernate, HSQL is faster than MySQL.
- A very good storage mechanism would be DB4O, which is also in-java,
and which can work directly with objects (an object oriented
database).
Converting from objects to tables and back is inefficient, and
communicating over JDBC adds even more overhead, while storing objects
directly is much faster. Also, complex/deep queries are the fastest in
this DB (see Barcelona/query, where DB4O is between 67 and 2500 (!)
times faster than HSQL+Hibernate, and up to 47000 times faster than
Derby *without* Hibernate). Artem, do you think you could try to
implement direct DB4O storage after you finish improving storage
refactoring and the query manager?
- At least in the versions used when this test was made, Derby (JavaDB
as it is called here) is among the slowest in most tests.
Could someone download PolePosition and run it on recent versions of
Derby and HSQLD, with Hibernate in front of them, to get some recent
comparison data?