3 Oct
2008
3 Oct
'08
6:34 p.m.
Artem Melentyev wrote:
Derby looks like a good choose, even it is probably
slower than hsqldb.
Derby is more powerful than hsqldb in some complex stuff like
transactions, sql fuctions and jdbc extensions.
We should test latest versions to see current performance of Derby.
Another variant is h2database.com which supposed to be faster than
hsqldb (h2 is fork of hsqldb). But it is less powerful than Derby too.
(no setCatalog)
So +1 for derby.
We could try to use db4o, but I think we shouldn't do it now. I think it
is not worthy effort for now. (new access api, no sql-like language)
I'll try it only after JCRStore will be done.
Yes, agreed, DB4O is just something that could be tried if there isn't
anything else to do.
Also I would like to propose to use UTF-8 as default
encoding for
standalone distribution.
AFAIK the major issue against utf8 is we can't control some parts like
DB or AppServer which configured for ISO for default (in some cases :)).
In standalone distribution we control everything, so there are no
problems with utf8.
(note: currently hsqldb and jetty works fine without explicit utf8
configuration. only xwiki.cfg, web.xml and hibernate.cfg.xml need to be
configured)
+111
Vincent Massol wrote:
--
Sergiu Dumitriu
http://purl.org/net/sergiu/
<snip>
For switching to Derby, I'm not convinced.
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
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?
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