On 7/10/06, Rob Davies <[EMAIL PROTECTED]> wrote:
Something we need to address for the Kaha persistent store is pluggable strategies for the indexing of data for both the List and Map container types.
+1 Currently, an IndexItem is a fixed size, but can be iterated as a bi-
directional linked list. The IndexItem holds offsets to the the data value and optional data key which is held in rolling data logs. Data values/keys are variable in length. When a Container is loaded, the IndexItem is loaded in to an in- memory structure - so for a Map Container a Map will hold the key - the value being the IndexItem - so that getting a data value involves looking up the IndexItem - then retrieving the data value associated with the IndexItem from disk. This works reasonably well and is fine medium size collections of messages (~20-30million with the default heap size for a message broker). But to ensure the Kaha Store can handle indexing larger number of messages with a relatively small memory footprint - we are obviously going to need something a little more sophisticated. Apart from a B-Tree - something that I've though about is using different types of caching - as the activemq message store really uses FIFO queues, a FIFO cache strategy would seem like a good strategy? thoughts ?
+1 cheers,
Rob
-- Regards, Hiram Blog: http://hiramchirino.com
