Tom,
in fact it is not that easy to switch to EclipseLink: TopLink is part of the
currently supported GFv2ur2, so users can just use it and will get support
for it (as part of the maintenance contract that one can buy from Sun).
Switching to EclipseLink means to have no more support for the JPA layer,
and to change the already installed and running GlassFish instances. So for
production environments it is a bit more complex than just repacing the
jar... :-)
Regards
Markus
> -----Original Message-----
> From: Tom Ware [mailto:tom.ware_at_oracle.com]
> Sent: Freitag, 12. Dezember 2008 14:32
> To: persistence_at_glassfish.dev.java.net
> Subject: Re: one performance issue on TopLink
>
> Hi Xiaojun,
>
> This issue is solved for Oracle, MySQL and PostGreSQL on EclipseLink.
>
> It is not clear to me why switching to EclipseLink would be difficult
> since it
> is just a matter of getting eclipselink.jar, switching persistence
> providers and
> renaming any proprietary API used (probably very little)
>
> If that is a problem, the other option is to take a look at the
> source code
> for OraclePlatform, MySQLPlatform or PostGreSQLPlatform in EclipseLink
> and build
> a subclass of the platform that is currently being used with the
> appropriate
> changes in Essentials.
>
> -Tom
>
> Xiaojun Zhang wrote:
> > Hello,
> >
> > One of our customers reported a performance issue.
> >
> > The performance remarkably deteriorates when the large value is
> > specified for the argument of Query#setFirstResult().
> >
> > Below are the execution time of retrieval result when specifying
> > different values of the argument.
> >
> > The start position of the result : The execution time of retrieval
> result
> >
> > setFirstResult(1) : 31 ms
> > setFirstResult(5000) : 297 ms
> > setFirstResult(50000) : 2875 ms
> >
> > The result showed the execution time increased when the value of
> start
> > position grew.
> >
> > Below is the result using Hibernate that shows there is no
> performance
> > deterioration occurred.
> >
> > setFirstResult(1) : 16 ms
> > setFirstResult(5000) : 15 ms
> > setFirstResult(50000) : 16 ms
> >
> > Assumed cause:
> > It seems that it takes much time on the processing of moving to a
> given
> > row of the ResultSet object by using java.sql.ResultSet.absolute.
> >
> > Since the current platform they are using is GlassFish v2 b58 it is
> > difficult to switch to EclipseLink. Could you someone please suggest
> a
> > fix plan for this.
> >
> > Regards,
> > Xiaojun