create dialect creates a cache of prepared queries for requests specialized for dialect.

• parameter dynamic_capacity

  is the sum weight of elements of the LRU used for dynamic requests below which trim will not attempt to release anything.

find_and_promote cache request promotes and returns the data associated with request in cache, if any.

Given the hard precondition that request is not bound in cache, as verified by find_and_promote, add cache request data binds it to data.

remove_and_discard cache request removes the binding for request from cache. The caller is assumed to have just extracted the element with find_and_promote and is resposible for releasing related resources.

deallocate request returns the entry for request, if any, along with a function to remove it from the cache.

iter f cache calls f on each element of cache.

elements cache is an arbitrarily ordered list of all elements, whether associated with a static or dynamic request.

trim ?promote_count cache carrious out some work trimming elements from the dynamic LRU cache. The call promotes up to max_promote_count elements, which are alive according to the garbage collector, and stop at the next one. It is up to the caller to free any resources associated with the returned elements.

clear cache removes all entries form cache. Elements are not returned, since this function may be used after a connection reset which invalidates the cached resources, but can be requested by calling elements first.