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From "James Johnson" <johnson.jam...@gmail.com>
Subject Re: Caching by pre-loading
Date Fri, 05 Jan 2007 00:32:13 GMT
Thanks for the quick response.

"iBATIS caches by SQL statement". I thought that was the case. Thanks for
confirming.

I'm trying to just use iBatis caching. One way that I saw of accomplishing
pre-loading was to issue the "select * from employee" at web application
startup. Then, on each user request for an employee(s), I re-executed the
"select * from employee". iBatis returns the cached results (I'm using a
queryForMap("getAllEmployee", null, "id")). Then I get the employees of
interest by using a get on the Map.

However, except for the first user request of a given employee, metrics seem
to show this to be slower than just querying "select * from employee where
id=#id#" for each employee.  Any ideas on how to use iBatis caching only and
have the first response to an user being cached data (pre-loading) while
having subsequent responses be at the speed of a cached "select * from
employee where id=#id#"? Perhaps, it's a situation where the best of both
worlds is not possible.



On 1/4/07, Jeff Butler <jeffgbutler@gmail.com> wrote:
>
> iBATIS caches by SQL statement - your two statements are different, so
> there is a cache miss.  This also demonstrates a fundamental truth about
> iBATIS - iBATIS doesn't know about object identity.  So iBATIS would have no
> way of looking through the first set of cached results to see if an object
> from the second statement already is available.
>
> You could accomplish what you want by loading all the employees into some
> cache that you manage - and then selecting individual employees from your
> cache.  Maybe your cache could just be a simple HashMap keyed by employee
> id?
>
> Jeff Butler
>
>
>
>
>
> On 1/4/07, James Johnson <johnson.james2@gmail.com> wrote:
> >
> > How does iBatis determine whether results are to be pulled from the
> > cache or to be queried from the database? For instance, if I have a
> > query like such: "select * from employee" and then follow-up with a second
> > query of "select * from employee where id=1", the second query appears to
> > hit the database instead of finding the employee object in the cache with
> > id=1. Is there way to have iBatis get the object from the cached results of
> > the 1st query? Both queries are in the same sqlMap xml have the same result
> > map.
> >
> > I'm trying to pre-load all employees at web application start so that
> > the first user request (for a given set of employees) doesn't take a hit
> > on response time. Most user requests are for 1-10 employees.
> >
> > Thanks in advance.
> >
>
>

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