29-11-2012, 10:57 PM
Answer:.Inter-query parallelism results from the ability to execute multiple queries at the same time while intra-query parallelism is achieved by breaking up a single query into a number of subqueries each of which is executed at a different site, accessing a different part of the distributed database.
If the user access to the distributed database consisted only of querying (i.e.,
read-only access), then provision of inter-query and intra-query parallelism would
imply that as much of the database as possible should be replicated. However, since most database accesses are not read-only, the mixing of read and update operations requires the implementation of elaborate concurrency control and commit protocols.
