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From "Kevin Sutter" <kwsut...@gmail.com>
Subject Re: Eager fetching not working with enums and lobs
Date Mon, 09 Jul 2007 16:17:58 GMT
:-)  The only reason why I would want to eagerly fetch LOBs is to satisfy
the intent of the spec.  Since the @Basic annotation is optional and the
default fetchType is EAGER, then I assert that the spec indicates that LOBs
need to be fetched EAGERly.  Do you read the spec differently?

I will agree that "in practice" LOBs should not be fetched EAGERly.  But, we
need to be consistent with the spec so as not to surprise customers as they
move from one JPA implementation to another.

Kevin

On 7/9/07, Patrick Linskey <plinskey@gmail.com> wrote:
>
> Indeed you do... why would we want to eagerly fetch LOBs? I understand
> the logic if @Basic is specified, but not if it is omitted.
>
> -Patrick
>
> On 7/9/07, Kevin Sutter <kwsutter@gmail.com> wrote:
> > I have opened JIRA Issue 281 (
> > https://issues.apache.org/jira/browse/OPENJPA-281) for this problem.  It
> > seems that we have agreed that enums should be EAGER by default.  I just
> > have to convince everybody that lobs also have to be EAGER, by
> default...
> > :-)
> >
> > Thanks,
> > Kevin
> >
> > On 7/8/07, Kevin Sutter <kwsutter@gmail.com> wrote:
> > >
> > > Craig,
> > > Comments below...
> > >
> > > On 7/7/07, Craig L Russell <Craig.Russell@sun.com> wrote:
> > > >
> > > > Hi Kevin,
> > > >
> > > > If you can figure out what the spec (9.1.18 and 9.1.19) sez, my
> hat's
> > > > off to you. What a mudbake this is.
> > >
> > >
> > > Isn't that just standard order of business with these specs?  :-)
> > >
> > > Part of the issue is the annotation definition. If @Basic is
> > > > specified, and the user doesn't explicitly override the fetch type,
> > > > it appears to our annotation processor as if the user specified
> > > > EAGER. Even if @Basic is used with @Lob, if lazy is wanted, it has
> to
> > > > be explicitly stated.
> > >
> > >
> > > That's how I read the spec.  The first paragraph of 9.1.18 indicates
> that
> > > @Basic can be applied to any those types (enums and lob types
> included).
> > > The default fetchType is EAGER.  It also states that @Basic is
> optional.
> > > So, the way I read this is that we should be doing EAGER fetching for
> all of
> > > those listed types unless explicitly told to do otherwise via the LAZY
> > > fetchType via an @Basic annotation.
> > >
> > > Maybe we should discuss @Lob in more detail. It isn't obvious to me
> > > > that @Basic can always be used and we might have an option to choose
> > > > a better default for the fetch behavior if @Basic annotation is
> omitted.
> > >
> > >
> > > It seems to me that the spec is clear on the use and expectations of
> > > @Basic and the default fetchType of EAGER.  Unless there are other
> spec
> > > references that contradict the statements in 9.1.18...
> > >
> > > Craig
> > > >
> > > > On Jul 6, 2007, at 11:37 AM, Kevin Sutter wrote:
> > > >
> > > > > I guess the spec is a bit clearer on this than I first thought.
> > > > > Section
> > > > > 9.1.8 of the JPA spec indicates that @Basic is optional and
> applies
> > > > > to the
> > > > > following types:
> > > > >
> > > > > "..Java primitive types, wrappers of the primitive types,
> > > > > java.lang.String,
> > > > > java.math.BigInteger,
> > > > > java.math.BigDecimal, java.util.Date, java.util.Calendar,
> > > > > java.sql.Date,
> > > > > java.sql.Time, java.sql.Timestamp, byte[], Byte[], char[],
> Character
> > > > > [],
> > > > > enums, and any other type that implements Serializable."
> > > > >
> > > > > And, since the default fetch type for @Basic is EAGER, it looks
> > > > > like we need
> > > > > to do eager fetching for both @Enumerated and @Lob fields unless
> > > > > otherwise
> > > > > overridden by a LAZY fetch type (ie. @Basic(fetch=LAZY)).  Agree?
> > > > >
> > > > > Kevin
> > > > >
> > > > > On 7/6/07, Craig L Russell <Craig.Russell@sun.com > wrote:
> > > > >>
> > > > >>
> > > > >> On Jul 6, 2007, at 10:52 AM, Patrick Linskey wrote:
> > > > >>
> > > > >> > The spec doesn't seem to discuss it, but I think that lazy
is a
> > > > >> pretty
> > > > >> > good default behavior for @Lob field types -- typically
@Lob
> things
> > > > >> > are big, so you often don't want them in the default fetch
> graph.
> > > > >>
> > > > >> Enum is different, though. Enum should be eager fetching by
> default.
> > > > >>
> > > > >> Lazy fetching is optional, so we can decide what we want to do.
> It
> > > > >> seems that the existence of @Basic should not change our
> strategy.
> > > > >> And we should default to lazy fetching for Lob and eager fetching
> for
> > > >
> > > > >> Enum.
> > > > >>
> > > > >> Craig
> > > > >> >
> > > > >> > -Patrick
> > > > >> >
> > > > >> > On 7/6/07, Kevin Sutter <kwsutter@gmail.com> wrote:
> > > > >> >> I am finding that the supposed default action of Eager
> fetching is
> > > > >> >> not
> > > > >> >> happening with @Enumerated and @Lob fields.  If I explicitly
> > > > >> >> specify the
> > > > >> >> @Basic annotation, then the fields are eagerly fetched.
 But,
> > > > >> >> without this
> > > > >> >> extraneous @Basic, these fields are lazily loaded. 
This
> action
> > > > >> >> does not
> > > > >> >> seem to be consistent with the spec.  Nor, can I find
any
> mention
> > > > >> >> of this
> > > > >> >> alternate behavior in our OpenJPA manual.  Sounds like
a bug
> to
> > > > >> >> me.  Any
> > > > >> >> other insights?
> > > > >> >>
> > > > >> >> This works (eager loading kicks in):
> > > > >> >>
> > > > >> >>     @Basic @Enumerated(EnumType.STRING)
> > > > >> >>     private Gender gender;
> > > > >> >>
> > > > >> >> This does not work (lazy loading kicks in):
> > > > >> >>
> > > > >> >>     @Enumerated(EnumType.STRING)
> > > > >> >>     private Gender gender;
> > > > >> >>
> > > > >> >> I have also tried to use defaults (without any annotations),
> > > > >> and lazy
> > > > >> >> loading still kicks in:
> > > > >> >>
> > > > >> >>     private Gender gender;
> > > > >> >>
> > > > >> >> Thanks,
> > > > >> >> Kevin
> > > > >> >>
> > > > >> >
> > > > >> >
> > > > >> > --
> > > > >> > Patrick Linskey
> > > > >> > 202 669 5907
> > > > >>
> > > > >> Craig Russell
> > > > >> Architect, Sun Java Enterprise System
> http://java.sun.com/products/
> > > > >> jdo
> > > > >> 408 276-5638 mailto: Craig.Russell@sun.com
> > > > >> P.S. A good JDO? O, Gasp!
> > > > >>
> > > > >>
> > > > >>
> > > >
> > > > Craig Russell
> > > > Architect, Sun Java Enterprise System
> http://java.sun.com/products/jdo
> > > > 408 276-5638 mailto:Craig.Russell@sun.com
> > > > P.S. A good JDO? O, Gasp!
> > > >
> > > >
> > > >
> > >
> >
>
>
> --
> Patrick Linskey
> 202 669 5907
>

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