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From "Jeff Butler" <dhsc...@cstone.dhs.state.il.us>
Subject Re: Is iBatis Caching Broken???
Date Wed, 09 Feb 2005 15:25:13 GMT
Done  (IBATIS-70).

Thanks for the quick response!

Jeff

>>> clinton.begin@gmail.com 2/9/2005 9:13:51 AM >>>
Hi Jeff, 

You're absolutely right....but I thought this is what it did....after
all, we just use HashMaps (which handles collisions) as the underlying
implementation.

When the developer's intention is not equal to the application
behaviour, that is generally indicative of a bug.  :-)

...and I believe I've found it....at some point the strong equals()
implementation of CacheKey was removed.  Nasty.  :-(

Could you submit a JIRA request for this and we'll make sure it's
fixed in the next release?

Clinton



On Wed, 09 Feb 2005 09:02:37 -0600, Jeff Butler
<dhscn06@cstone.dhs.state.il.us> wrote:
> I found a problem recently related to iBatis caching.
> 
> I have a mapped select statement that takes one parameter, a string.
> I'm not using a parameter map, just passing the string in directly on
a
> queryForList() call.  I was using the LRU cache on that statement. 
I
> found that the statement was returning incorrect values in several
> cases.  It came down to this...two parameter strings yielded the
same
> hashCode, so iBatis caching thought they were the same string and
> incorrectly returned the value from the cache.
> 
> An example is the two strings "HS1CS001" and "HS1D4001".  Both
strings
> yield the same hashCode.  So the
com.ibatis.sqlmap.engine.cache.CacheKey
> class generated the same CacheKey for two different calls.  If the
> statement has already been called with "HS1CS001" as the parameter,
and
> is later called with "HS1D4001", then the result for the first call
will
> be returned from the cache on the second call.  Not good!
> 
> It seems to me that iBatis should not rely on hashCode to generate
its
> internal CacheKey since it is certainly allowable for different, and
> unequal, objects to return the same hashCode.  Hence my
question...is
> iBatis caching broken, or am I missing something?
> 
> Thanks for any ideas!
> Jeff Butler
> 
>

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