Page 30 of the SqlMaps manual states: Read-Only vs. Read/Write
The framework supports both read-only and read/write caches. Read-only caches are shared among all users and therefore offer greater performance benefit. However, objects read from a read-only cache should not be modified. Instead, a new object should be read from the database (or a read/write cache) for updating. On the other hand, if there is an intention to use objects for retrieval and modification, a read/write cache is recommended (i.e. required). To use a read-only cache, set readOnly="true" on the cache model element. To use a read/write cache, set readOnly="false". The default is read-only (true). Serializable Read/Write Caches As you may agree, caching per-session as described above may offer little benefit to global application performance. Another type of read/write cache that can offer a performance benefit to the entire application (i.e. not just per session) is a serializable read/write cache. This cache will return different instances (copies) of the cached object to each session. Therefore each session can safely modify the instance returned. Realize the difference in semantics here, usually you would expect the same instance to be returned from a cache, but in this case you'll get a different one. Also note that every object stored by a serializable cache must be serializable. This means that you will have difficulty using both lazy loading features combined with a serializable cache, because lazy proxies are not serializable. The best way to figure out what combination of caching, lazy loading and table joining is simply to try it out. To use a serializable cache, set readOnly="false" and serialize="true". By default cache models are read-only and non-serializable. Read-only caches will not be serialized (there's no benefit). Hope that helps, Brandon On Thu, 16 Dec 2004 23:49:55 -0600, Barnett, Brian W. <[EMAIL PROTECTED]> wrote: > Let me see if I understand this correctly... > > I get a list object back from a call to executeQueryForList(). I have > caching enabled in ibatis, so ibatis caches the list, or a reference to it. > As long as the cache has not been flushed, if I make another call to the > same mapped statement using executeQueryForList(), it returns the same list, > not a separate copy of the list but the same one as before. > > I then modify the contents of this list, but nothing has been updated in the > database yet. Another user logs into the system and calls that same mapped > statement. He will get the list that has the modifications made by the first > user, even though nothing has been updated in the database. Is this correct? > I think this is the behavior I'm seeing. > > So, what is best practice to avoid this? Should I make deep copies of all > objects returned from ibatis if I am using caching? What are my options? > > Thanks, > Brian Barnett >
