Would you *always* come back and get the entire list if you determine that the last 10 are new?
On Tue, Jan 19, 2010 at 2:42 PM, jim <jim.basi...@gmail.com> wrote: > It's not a matter of memcached being bad, it's a matter of pulling > only X items off the big list in order to perform more efficiently. > Sometimes we want the entire list .. but also sometimes we just want > to look at the last 10 and see if there are new items vs. pulling the > entire list across the network and looking at only the top few items. > > It seems since memcached (at least for text serialization) is just > storing serialized bytes I could say give me X byte chunks and my app > would know how to do the deserialization. At least I THINK this > sounds feasible. > > On Jan 19, 12:20 pm, Boris Partensky <boris.parten...@gmail.com> > wrote: > > Can you always invalidate memcached entry when a new item is inserted > into > > the list? This way you can assume that what's in memcached is always > good. > > > > Boris > > > > > > > > On Tue, Jan 19, 2010 at 9:11 AM, jim <jim.basi...@gmail.com> wrote: > > > Hi: > > > > > I've recently started on a project that is utilizing memcached to > > > buffer lists of 'long's that represent key values for larger more > > > detailed objects to load if needed. This list will have a maximum of > > > 10,000 items. > > > > > ex: > > > > > List of longs: > > > key : actList value : maximum 10,000 longs sorted chronologically > > > based on their 'detailed' object timestamp. > > > > > Detailed entry: > > > key : act_<id> value : text serialized object representing detailed > > > activity object. <id> is contained on the 'List of longs' above. > > > > > My question is there are times where we would like to load only the > > > first block of entries from the list of longs, say 10 records. We > > > would then look at those 10 records and see if they are new based on > > > what a currently displayed list shows and if so grab these new entries > > > without pulling all 10,000 across from cache only to utilize the > > > relatively small number of new entries on the top of the list. This > > > kind of goes hand in hand with the prepend (or append) operations > > > where when new activities arrive we push these new activities into the > > > front of the 'List of longs' and it's these new entries that clients > > > may be interested in if they do not yet have them. > > > > > My question is, is there a way to do this? Is there a way to grab > > > only X bytes from a value in memcache? I read over the protocol > > > document and it doesn't appear there is. Is there any interest or > > > valid use case that this seems to fill for other users? > > > > > An alternate solution I can see if to store the 'list of longs' as a > > > flat list of keys with a naming convention, such as actList_1, > > > actList_2, etc. However, this will obviously lead to an extremely > > > long key name in the multi-key 'get' as well as lots of churn in > > > managing these objects .. so it appears far less than ideal. However, > > > we have many (200,000) lists of these 10,000 item 'List of longs' > > > which leads to pulling loads of data over the wire when a large update > > > occurs that needs to be communicated with cache ... it would be much > > > more efficient to only go after a certain number of bytes in cache vs. > > > the entire cached value. > > > > > Any other thoughts? Ideas? > > > > > Thank you. > > > Jim > > > > -- > > --Boris > -- --Boris
