On 30 Jan 2006, at 10:29, Jules Gosnell wrote:
James Strachan wrote:
On 30 Jan 2006, at 10:06, Jules Gosnell wrote:
Finally, as discussed with James on numerous occasions, we
should look at how WADI's pessimistic locking and
PartitionManager might be componentised so that they can be
plugged into AS to provide Cache and Space users, who are not
interested in location- independance, with a pessimistic approach
and/or a partitioned clustering substrate...
BTW I don't see using a pessimistic lock as being very useful for
a cache; typically in a JCache scenario you are caching state
that is stored in some database/system; so if you really want a
pessimistic lock you should lock the database (they are very good
at doing distributed locks) rather than having a pessimistic lock
in a cache which is a different lock to where the actual data is.
Agreed - but in the case of a distributed session, it may not be
mapped to a database.... - I guess we are not a typical JCache
scenario ?
Exactly. JCache is usually used for distributed caching of persistent
state. So for most users of JCache, pessimistic locking has no real
value.
The exception to this rule is for folks who want to use JCache as a
database (being the master copy of the state) which is usually as a
result of folks trying to solve the distributed-session-state
problem. But its much better IMHO to just solve the distributed
session state problem correctly than turn JCache into a database :)
James
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