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Posted to user-java@ibatis.apache.org by Larry Meadors <lm...@apache.org> on 2007/06/06 12:59:47 UTC
Re: Cache object reference
On 6/6/07, Meindert <me...@pastelebusiness.com> wrote:
> Is it by design that the object returned from the cache has the same object
> reference as the on in the cache?
Yes, it is. This is intended to be a performance enhancing tweak for
the brave, but in your case it is a misconfiguration.
In your cache definition, you have readonly="true", but are not
modifying the results. You are a very bad boy. Don't do that. :-)
If you set serializable="true" and readonly="false" then the object is
copied before being returned from the cache - assuming that the cached
objects are serializable - if they are not, KABOOM!
Note: If you set serializable="false" and readonly="false", you will
lose a lot of caching benefits, because results will only be cached
for the current iBATIS 'session', which is in 99.999% of cases, not
what you want. Don't do that either. :-)
Larry
Re: Cache object reference
Posted by Larry Meadors <lm...@apache.org>.
<shameless-plug>Ya, it's in the book, buy it! :-)</shameless-plug>
http://www.amazon.com/gp/product/1932394826?ie=UTF8&tag=ai0e-20&link_code=as3&camp=211189&creative=373489&creativeASIN=1932394826
Larry
On 6/6/07, Gwyn Evans <gw...@gmail.com> wrote:
> On Wednesday, June 6, 2007, 11:59:47 AM, Larry <lm...@apache.org> wrote:
>
> > On 6/6/07, Meindert <me...@pastelebusiness.com> wrote:
> >> Is it by design that the object returned from the cache has the same object
> >> reference as the on in the cache?
>
> > In your cache definition, you have readonly="true", but are not
> > modifying the results. You are a very bad boy. Don't do that. :-)
>
> Don't you mean "but are modifying the results"? :-)
>
> Anyway, for the OP, Larry's obviously too polite, but "iBATIS in
> Action" has a good explanation about this (and a lot else) - See
> section 9.3.4 on p200.
>
> /Gwyn
>
>
Re: Cache object reference
Posted by Gwyn Evans <gw...@gmail.com>.
On Wednesday, June 6, 2007, 11:59:47 AM, Larry <lm...@apache.org> wrote:
> On 6/6/07, Meindert <me...@pastelebusiness.com> wrote:
>> Is it by design that the object returned from the cache has the same object
>> reference as the on in the cache?
> In your cache definition, you have readonly="true", but are not
> modifying the results. You are a very bad boy. Don't do that. :-)
Don't you mean "but are modifying the results"? :-)
Anyway, for the OP, Larry's obviously too polite, but "iBATIS in
Action" has a good explanation about this (and a lot else) - See
section 9.3.4 on p200.
/Gwyn
RE: Cache object reference
Posted by Meindert <me...@pastelebusiness.com>.
Ah! Excellent that is better then cloning the result object! Thanks!
Must say though, I don't understand the whole caching..
> In your cache definition, you have readonly="true", but are not
> modifying the results. You are a very bad boy. Don't do that. :-)
Readonly="true" is the default so I thought that is the 'normal' setting
I have a readonly cache and are only reading (not modifying) the result,
sounds right doesn't it?
I also tried Readonly="false" but this (without serializable=true) did not
'fix' the issue.
I flush the cache when I do an update. And therefore don't need to write to
the cache? Am I misusing the cache functionality in this way?
The example on page 42 of the developer guide states readOnly="true"
serialize="false", this is a bad configuration?
> because results will only be cached for the current iBATIS 'session'
I'm running iBATIS in a web application, isn't there only one iBATIS
'session'? (When I start the web application for the first time)
Kind Regards
Meindert
-----Original Message-----
From: larry.meadors@gmail.com [mailto:larry.meadors@gmail.com] On Behalf Of
Larry Meadors
Sent: 06 June 2007 01:00 PM
To: user-java@ibatis.apache.org
Subject: Re: Cache object reference
On 6/6/07, Meindert <me...@pastelebusiness.com> wrote:
> Is it by design that the object returned from the cache has the same
object
> reference as the on in the cache?
Yes, it is. This is intended to be a performance enhancing tweak for
the brave, but in your case it is a misconfiguration.
In your cache definition, you have readonly="true", but are not
modifying the results. You are a very bad boy. Don't do that. :-)
If you set serializable="true" and readonly="false" then the object is
copied before being returned from the cache - assuming that the cached
objects are serializable - if they are not, KABOOM!
Note: If you set serializable="false" and readonly="false", you will
lose a lot of caching benefits, because results will only be cached
for the current iBATIS 'session', which is in 99.999% of cases, not
what you want. Don't do that either. :-)
Larry