3:54 a.m.
In regards to : postgresql - is it reasonable to require this uuid-ossp
module?
In my experience, I avoided using the uuid-ossp module and just used
java.util.UUID.randomUUID() in my
model class to generate my uuid for me instead having the database generate
the uuid.
Depending on how much access rights you have to your database, you might be
able
to easily install uuid-ossp. On the other hand even if you have rights to
install it,
you may wish to avoid taking any maintenance down time which may be
required.
Regards,
Dave
On Thu, May 27, 2010 at 8:01 AM, <hibernate-dev-request(a)lists.jboss.org>wrote:
Send hibernate-dev mailing list submissions to
hibernate-dev(a)lists.jboss.org
To subscribe or unsubscribe via the World Wide Web, visit
https://lists.jboss.org/mailman/listinfo/hibernate-dev
or, via email, send a message with subject or body 'help' to
hibernate-dev-request(a)lists.jboss.org
You can reach the person managing the list at
hibernate-dev-owner(a)lists.jboss.org
When replying, please edit your Subject line so it is more specific
than "Re: Contents of hibernate-dev digest..."
Today's Topics:
1. Optimizing reflection optimization (?????? ????????)
2. Database with UUID support (Steve Ebersole)
3. Re: Optimizing reflection optimization (Emmanuel Bernard)
4. Re: Database with UUID support (Cody Lerum)
5. Re: Database with UUID support (Steve Ebersole)
6. Re: Database with UUID support (Emmanuel Bernard)
7. Re: Database with UUID support (Steve Ebersole)
8. Re: Database with UUID support (Steve Ebersole)
----------------------------------------------------------------------
Message: 1
Date: Wed, 26 May 2010 19:29:01 +0300
From: ?????? ???????? <kirill.klenski(a)gmail.com>
Subject: [hibernate-dev] Optimizing reflection optimization
To: hibernate-dev(a)lists.jboss.org
Message-ID:
<AANLkTimK4Aorz1EfWODJPwNo0f7HYGFO9DgWK3YvNZPb(a)mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Hi,
Recently my task involved enabling hibernate reflection optimization in our
application.
Versions used:
hibernate-core-3.3.1.GA
javassist-3.4.GA
Below are some thoughts that hopefully could help to improve the product.
1. I have noticed that
org.hibernate.bytecode.javassist.BulkAccessorFactory.findAccessors(...) is
searching for accessor methods in the optimized entity class only. This
means that the methods from the superclasses are not visible during
BulkAccessor creation unless overridden by child classes. By enhancing the
algorithm to search down the inheritance tree we could avoid creation of
redundant methods which increase the code verbosity a lot. In our case
almost all the entities are inherited from the base classes having the
common entity properties defined, so the reflection optimization does not
work for any of them until we override the inherited methods in all the
child classes. The implementation is trivial, but I have got a ready
prototype if anybody is interested.
2. It seems that it should be also possible to optimize the
EntityTuplizer's
getPropertyValue and setPropertyValue calls in the similar way how the
getPropertyValues and setPropertyValues are currently optimized.
Best regards,
Kirill Klenski
------------------------------
Message: 2
Date: Wed, 26 May 2010 15:24:46 -0500
From: Steve Ebersole <steve(a)hibernate.org>
Subject: [hibernate-dev] Database with UUID support
To: "hibernate-dev(a)lists.jboss.org" <hibernate-dev(a)lists.jboss.org>
Message-ID: <1274905486.21430.72.camel@apollo>
Content-Type: text/plain; charset="UTF-8"
In regards to
http://opensource.atlassian.com/projects/hibernate/browse/HHH-3579 I am
trying to put together the best all around support for java.util.UUID we
can as a type.
Obviously most databases "support uuid" via char/varchar data type.
Postgresql being the lone exception of which I am aware with their
special UUID datatype, even though they choose to map it to
java.sql.Types.OTHER (don't get me started). So for sure we can support
UUID in every database.
The next logical thought was supporting UUID as an identifier value. If
we were to add that what I would really prefer is a way to obtain the
UUID ahead of time (pre-insert) which would mean knowing what databases
supported a UUID-generation function and, for those that did, what that
function is. For those that do not, is using
java.util.UUID.randomUUID() a viable alternative?
A list of major databases and their support/non-support for generating
UUID values that I know of are as follows:
1) postgresql - database itself does not support generation, instead
relying on an optional module called uuid-ossp
2) mysql - supports generation via the UUID() function
3) h2 - supports generation via the RANDOM_UUID()
4) hsqldb - does not support generation afaict
5) derby - does not support generation afaict
6) db2 - does have a GENERATE_UNIQUE() function; was not able to tell if
that is compatible with java.util.UUID
7) firebird - supports generation via GEN_UUID()
8) informix - does not support generation afaict
9) ingres - supports via UUID_CREATE()
10) oracle - supports via SYS_GUID()
11) maxdb (sapdb) - does not support generation afaict
12) mssql (sql server) - does have a NEWID() function, though it
generates a string with hyphons in it; not sure how/if this value
relates to java.util.UUID
13) sybase - like mssql also has a NEWID() function which here can
additionally be given a parameter to say whether to include hyphons etc;
again, not sure how/if this value relates to java.util.UUID
14) terradata - does not support generation afaict
DISCLAIMER : When I say "does not support" I mean in the base server
install. As I pointed out with postgresql I understand some might have
additional optional or third-party modules that add such capabilities
So by my count, that means that we can have pretty complete support for
UUID on the following databases without any extra requirements:
a) mysql
b) h2
c) firebird
d) ingres
e) oracle
Databases with potential support:
a) postgresql - is it reasonable to require this uuid-ossp module?
b) db2 - what is the compatibility of its GENERATE_UNIQUE() function
with java.util.UUID?
c) mssql/sybase - what is the compatibility of NEWID() function with
with java.util.UUID?
For databases which do not support UUID generation, the question becomes
how do we support that in hibernate for identifiers? Do we rely on
java.util.UUID.randomUUID()? Do you use a special generator like
http://jug.safehaus.org/ ? Other options?
Also, if anyone notices issues in my db support investigations please
let me know.
--
Steve Ebersole <steve(a)hibernate.org>
http://hibernate.org
------------------------------
Message: 3
Date: Wed, 26 May 2010 22:53:32 +0200
From: Emmanuel Bernard <emmanuel(a)hibernate.org>
Subject: Re: [hibernate-dev] Optimizing reflection optimization
To: ?????? ???????? <kirill.klenski(a)gmail.com>
Cc: hibernate-dev(a)lists.jboss.org
Message-ID: <C953A377-1572-4A88-8D16-B24ED07B387E(a)hibernate.org>
Content-Type: text/plain; charset=utf-8
Hi,
Have you noticed a perf difference in your application with and without the
patch?
I am wondering if modern VMs have catched up with what Javassist does.
On 26 mai 2010, at 18:29, ?????? ???????? wrote:
> 1. I have noticed that
> org.hibernate.bytecode.javassist.BulkAccessorFactory.findAccessors(...)
is
> searching for accessor methods in the optimized entity class only. This
> means that the methods from the superclasses are not visible during
> BulkAccessor creation unless overridden by child classes. By enhancing
the
> algorithm to search down the inheritance tree we could avoid creation of
> redundant methods which increase the code verbosity a lot. In our case
> almost all the entities are inherited from the base classes having the
> common entity properties defined, so the reflection optimization does not
> work for any of them until we override the inherited methods in all the
> child classes. The implementation is trivial, but I have got a ready
> prototype if anybody is interested.
------------------------------
Message: 4
Date: Wed, 26 May 2010 15:30:00 -0600
From: Cody Lerum <cody.lerum(a)gmail.com>
Subject: Re: [hibernate-dev] Database with UUID support
To: Steve Ebersole <steve(a)hibernate.org>
Cc: "hibernate-dev(a)lists.jboss.org" <hibernate-dev(a)lists.jboss.org>
Message-ID:
<AANLkTikQJ294O2IKpWye4lWYh9DvC6rpCujvyIk7cHnv(a)mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
I prefer time based (version 1) UUID due the insert performance of random
ID's.
Though that sends you down the road of using a third party generator.
FWIW http://johannburkard.de/software/uuid/ is recommended on the
Apache Cassandra wiki.
On Wed, May 26, 2010 at 2:24 PM, Steve Ebersole <steve(a)hibernate.org>
wrote:
> In regards to
> http://opensource.atlassian.com/projects/hibernate/browse/HHH-3579 I am
> trying to put together the best all around support for java.util.UUID we
> can as a type.
>
> Obviously most databases "support uuid" via char/varchar data type.
> Postgresql being the lone exception of which I am aware with their
> special UUID datatype, even though they choose to map it to
> java.sql.Types.OTHER (don't get me started). ?So for sure we can support
> UUID in every database.
>
> The next logical thought was supporting UUID as an identifier value. ?If
> we were to add that what I would really prefer is a way to obtain the
> UUID ahead of time (pre-insert) which would mean knowing what databases
> supported a UUID-generation function and, for those that did, what that
> function is. ?For those that do not, is using
> java.util.UUID.randomUUID() a viable alternative?
>
> A list of major databases and their support/non-support for generating
> UUID values that I know of are as follows:
>
> 1) postgresql - database itself does not support generation, instead
> relying on an optional module called uuid-ossp
> 2) mysql - supports generation via the UUID() function
> 3) h2 - supports generation via the RANDOM_UUID()
> 4) hsqldb - does not support generation afaict
> 5) derby - does not support generation afaict
> 6) db2 - does have a GENERATE_UNIQUE() function; was not able to tell if
> that is compatible with java.util.UUID
> 7) firebird - supports generation via GEN_UUID()
> 8) informix - does not support generation afaict
> 9) ingres - supports via UUID_CREATE()
> 10) oracle - supports via SYS_GUID()
> 11) maxdb (sapdb) - does not support generation afaict
> 12) mssql (sql server) - does have a NEWID() function, though it
> generates a string with hyphons in it; not sure how/if this value
> relates to java.util.UUID
> 13) sybase - like mssql also has a NEWID() function which here can
> additionally be given a parameter to say whether to include hyphons etc;
> again, not sure how/if this value relates to java.util.UUID
> 14) terradata - does not support generation afaict
>
> DISCLAIMER : When I say "does not support" I mean in the base server
> install. ?As I pointed out with postgresql I understand some might have
> additional optional or third-party modules that add such capabilities
>
>
> So by my count, that means that we can have pretty complete support for
> UUID on the following databases without any extra requirements:
> a) mysql
> b) h2
> c) firebird
> d) ingres
> e) oracle
>
> Databases with potential support:
> a) postgresql - is it reasonable to require this uuid-ossp module?
> b) db2 - what is the compatibility of its GENERATE_UNIQUE() function
> with java.util.UUID?
> c) mssql/sybase - what is the compatibility of NEWID() function with
> with java.util.UUID?
>
> For databases which do not support UUID generation, the question becomes
> how do we support that in hibernate for identifiers? ?Do we rely on
> java.util.UUID.randomUUID()? ?Do you use a special generator like
> http://jug.safehaus.org/ ? ?Other options?
>
> Also, if anyone notices issues in my db support investigations please
> let me know.
>
> --
> Steve Ebersole <steve(a)hibernate.org>
> http://hibernate.org
>
> _______________________________________________
> hibernate-dev mailing list
> hibernate-dev(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>
------------------------------
Message: 5
Date: Wed, 26 May 2010 20:13:48 -0500
From: Steve Ebersole <steve(a)hibernate.org>
Subject: Re: [hibernate-dev] Database with UUID support
To: Cody Lerum <cody.lerum(a)gmail.com>
Cc: "hibernate-dev(a)lists.jboss.org" <hibernate-dev(a)lists.jboss.org>
Message-ID: <1274922828.21430.94.camel@apollo>
Content-Type: text/plain; charset="UTF-8"
The main drawback there imo is that it uses its own UUID implementation
(com.eaio.uuid.UUID) rather than simply generating java.util.UUID. To
do so you have "bridge" as pointed out in the Cassandra FAQ:
http://wiki.apache.org/cassandra/FAQ#working_with_timeuuid_in_java
Not to mention the maven information he lists is inaccurate (there is no
repo at http://eaio.com/maven2) and the latest posts on that website are
from 2007.
On Wed, 2010-05-26 at 15:30 -0600, Cody Lerum wrote:
> I prefer time based (version 1) UUID due the insert performance of random
ID's.
>
> Though that sends you down the road of using a third party generator.
> FWIW http://johannburkard.de/software/uuid/ is recommended on the
> Apache Cassandra wiki.
>
> On Wed, May 26, 2010 at 2:24 PM, Steve Ebersole <steve(a)hibernate.org>
wrote:
> > In regards to
> > http://opensource.atlassian.com/projects/hibernate/browse/HHH-3579 I
am
> > trying to put together the best all around support for java.util.UUID
we
> > can as a type.
> >
> > Obviously most databases "support uuid" via char/varchar data type.
> > Postgresql being the lone exception of which I am aware with their
> > special UUID datatype, even though they choose to map it to
> > java.sql.Types.OTHER (don't get me started). So for sure we can
support
> > UUID in every database.
> >
> > The next logical thought was supporting UUID as an identifier value.
If
> > we were to add that what I would really prefer is a way to obtain the
> > UUID ahead of time (pre-insert) which would mean knowing what databases
> > supported a UUID-generation function and, for those that did, what that
> > function is. For those that do not, is using
> > java.util.UUID.randomUUID() a viable alternative?
> >
> > A list of major databases and their support/non-support for generating
> > UUID values that I know of are as follows:
> >
> > 1) postgresql - database itself does not support generation, instead
> > relying on an optional module called uuid-ossp
> > 2) mysql - supports generation via the UUID() function
> > 3) h2 - supports generation via the RANDOM_UUID()
> > 4) hsqldb - does not support generation afaict
> > 5) derby - does not support generation afaict
> > 6) db2 - does have a GENERATE_UNIQUE() function; was not able to tell
if
> > that is compatible with java.util.UUID
> > 7) firebird - supports generation via GEN_UUID()
> > 8) informix - does not support generation afaict
> > 9) ingres - supports via UUID_CREATE()
> > 10) oracle - supports via SYS_GUID()
> > 11) maxdb (sapdb) - does not support generation afaict
> > 12) mssql (sql server) - does have a NEWID() function, though it
> > generates a string with hyphons in it; not sure how/if this value
> > relates to java.util.UUID
> > 13) sybase - like mssql also has a NEWID() function which here can
> > additionally be given a parameter to say whether to include hyphons
etc;
> > again, not sure how/if this value relates to java.util.UUID
> > 14) terradata - does not support generation afaict
> >
> > DISCLAIMER : When I say "does not support" I mean in the base server
> > install. As I pointed out with postgresql I understand some might have
> > additional optional or third-party modules that add such capabilities
> >
> >
> > So by my count, that means that we can have pretty complete support for
> > UUID on the following databases without any extra requirements:
> > a) mysql
> > b) h2
> > c) firebird
> > d) ingres
> > e) oracle
> >
> > Databases with potential support:
> > a) postgresql - is it reasonable to require this uuid-ossp module?
> > b) db2 - what is the compatibility of its GENERATE_UNIQUE() function
> > with java.util.UUID?
> > c) mssql/sybase - what is the compatibility of NEWID() function with
> > with java.util.UUID?
> >
> > For databases which do not support UUID generation, the question
becomes
> > how do we support that in hibernate for identifiers? Do we rely on
> > java.util.UUID.randomUUID()? Do you use a special generator like
> > http://jug.safehaus.org/ ? Other options?
> >
> > Also, if anyone notices issues in my db support investigations please
> > let me know.
> >
> > --
> > Steve Ebersole <steve(a)hibernate.org>
> > http://hibernate.org
> >
> > _______________________________________________
> > hibernate-dev mailing list
> > hibernate-dev(a)lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/hibernate-dev
> >
--
Steve Ebersole <steve(a)hibernate.org>
http://hibernate.org
------------------------------
Message: 6
Date: Thu, 27 May 2010 08:27:47 +0200
From: Emmanuel Bernard <emmanuel(a)hibernate.org>
Subject: Re: [hibernate-dev] Database with UUID support
To: hibernate-dev(a)lists.jboss.org
Message-ID: <4E2E28D3-0EBD-4826-AFCC-F5E562730654(a)hibernate.org>
Content-Type: text/plain; charset=us-ascii
To his credit a UUID impl is not a 10 year project plan ;) I would not
necessarily consider it abandonware rather than done.
On 27 mai 2010, at 03:13, Steve Ebersole wrote:
> and the latest posts on that website are
> from 2007.
------------------------------
Message: 7
Date: Thu, 27 May 2010 06:12:40 -0500
From: "Steve Ebersole" <steve(a)hibernate.org>
Subject: Re: [hibernate-dev] Database with UUID support
To: "Emmanuel Bernard" <emmanuel(a)hibernate.org>,
"hibernate-dev(a)lists.jboss.org" <hibernate-dev(a)lists.jboss.org>
Message-ID: <4bfe53af.8c43e70a.68d9.2a1d(a)mx.google.com>
Content-Type: text/plain; charset=UTF-8
The site is not just about the UUID generator project. He wrote posts
on ohter subjects as well.
My point there is more to the maven repo. How do we reference this?
Are we ending up hosting another artifact? How do we even
contact him to find out?
-- Sent from my Palm Pre
steve(a)hibernate.org
http://hibernate.orgOn May 27, 2010 1:28 AM, Emmanuel Bernard &
lt;emmanuel(a)hibernate.org <lt%3Bemmanuel(a)hibernate.org>&gt; wrote:
To his credit a UUID impl is not a 10 year project plan ;) I would not
necessarily consider it abandonware rather than done.
On 27 mai 2010, at 03:13, Steve Ebersole wrote:
> and the latest posts on that website are
> from 2007.
_______________________________________________
hibernate-dev mailing list
hibernate-dev(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/hibernate-dev
------------------------------
Message: 8
Date: Thu, 27 May 2010 07:01:49 -0500
From: Steve Ebersole <steve(a)hibernate.org>
Subject: Re: [hibernate-dev] Database with UUID support
To: Emmanuel Bernard <emmanuel(a)hibernate.org>
Cc: "hibernate-dev(a)lists.jboss.org" <hibernate-dev(a)lists.jboss.org>
Message-ID: <1274961709.21430.116.camel@apollo>
Content-Type: text/plain; charset="UTF-8"
Anyway, the discussion here wrt this UUID project is all about
generating the UUID value in Java. The first point is to determine
whether there is any benefit to relying on the database to generate
these for us in the cases when they can.
Secondly there is the question of if we are going to do it in Java then
what is the correct approach. Both libraries mentioned here (UUID and
JUG) use MAC address resolution in building the uuid value. JUG is
updating to use java.util.UUID, but relies on native code for
mac-address-resoltion; UUID use its own UUID class but does not need
native code for the mac-address-resolution (it uses OS-sniffing and
system calls). Heck maybe we offer this as a strategy configurable with
the Configuration/SessionFactory.
interface UUIDGenerationStrategy extends Serializable {
public int getGenerationVersion(); // informational
public UUID generateUUID(SessionImplementor session);
}
But first things first...
Do we use database uuid generation if supported? Is that itself perhaps
just a strategy?
On Thu, 2010-05-27 at 06:12 -0500, Steve Ebersole wrote:
> The site is not just about the UUID generator project. He wrote posts
> on ohter subjects as well.
>
> My point there is more to the maven repo. How do we reference this?
> Are we ending up hosting another artifact? How do we even contact
> him to find out?
>
>
>
>
>
> -- Sent from my Palm Pre
>
> steve(a)hibernate.org
> http://hibernate.org
> ______________________________________________________________________
> On May 27, 2010 1:28 AM, Emmanuel Bernard <emmanuel(a)hibernate.org>
> wrote:
>
> To his credit a UUID impl is not a 10 year project plan ;) I would not
> necessarily consider it abandonware rather than done.
>
> On 27 mai 2010, at 03:13, Steve Ebersole wrote:
>
> > and the latest posts on that website are
> > from 2007.
>
>
> _______________________________________________
> hibernate-dev mailing list
> hibernate-dev(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/hibernate-dev
--
Steve Ebersole <steve(a)hibernate.org>
http://hibernate.org
------------------------------
_______________________________________________
hibernate-dev mailing list
hibernate-dev(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/hibernate-dev
End of hibernate-dev Digest, Vol 47, Issue 18
*********************************************
--
David J. Driscoll
www.EnduroTracker.com
EnduroTracker.BlogSpot.com
www.google.com/profiles/Driscoll.DavidJ