ES> Are cached slots usable yet (at least in a single-threaded situation)? When I use ":cached t" in my slot definitions, I get errors.
i postmodern backend rather than doing caching on a slot level we're doing it on btree level. that is, get-value and (setf get-value) functions do lookups/writes in a cache hash table ((btree-id, key) -> value), and this works pretty well, as everything gets cached. if underlying hash table is weak, it could automatically control its size. the tricky thing, however, is to do it in transaction-safe way. simpliest way to do it transaction-safe is to use cache only within a single transaction, and throw it out afterwards -- then you'll never have stale entries. that doesn't work well of you have lots of small transactions, though. db-postmodern has a caching mode where it does additional changes tracking to invalidate cache entries properly. but if you know that your application is single-threaded, for example, you can do it in easier way -- just keep using single cache as long as no transactions do rollback, if they do rollback you'll have to delete it. with multiple threads in single process you can handle this via relatively easy invalidation protocol, i guess. (i'm not sure how exactly, though, at moment, as i'm more familiar with MVCC concurrency model rather than bdb's lock based. maybe with lock based model you don't have to do much.) so, what i was going to say, adding caching for your specific application can be fairly easy -- you just need to instrument db-bdb code a little, adding just a few dozen of lines of code. so you can just try to do this, instead of relying on weird slot-caching protocol. _______________________________________________ elephant-devel site list elephant-devel@common-lisp.net http://common-lisp.net/mailman/listinfo/elephant-devel
