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In-Depth Information
key to the server (to be installed into the global lock table) otherwise. Work out this
extension to the caching and locking protocols.
14.7
With the extended caching and locking protocols discussed in the previous
exercise, we can allow a previous version of a page that is currently cached for
updating at a client to be cached for reading at other clients. Work out this relaxed
caching protocol.
14.8
A shared-disks system must keep track, for each node, of the pages buffered
and the modes of buffering and of the locks held at that node. In other words, a
shared-disks system must maintain the equivalents of the cached-page table and the
global lock table of a page-server system. Where are these tables kept and how are
they managed during normal processing and after recovery from failure at one node?
Bibliographical Notes
DeWitt et al. [
1990
] analyze the three alternative designs for a data-shipping client-
server architecture: the object server, page server, and file server. Of these, the
page server has been found to be the simplest to implement, and it can utilize the
clustering of objects in pages [Franklin et al.,
1996
]. Different methods such as
callbacks for ensuring cache consistency in page-server and shared-disks systems
are reviewed and analyzed by Franklin et al. [
1997
].
Most of the material in this chapter comes from the article by Mohan and Narang
[
1994
] that describes
ARIES/CSA
,the
ARIES
algorithm for client-server architectures.
A different design of an
ARIES
-compatible page-server system has been imple-
mented in the client-server version of the
EXODUS
storage manager [Franklin et al.
1992
]. The page-transfer methods for shared-disks systems mentioned in Sect.
14.10
are discussed in detail by Mohan and Narang [
1991
].
Carey et al. [
1994
] and Zaharioudakis et al. [
1997
] analyze different caching
protocols for page-server environments with fine-grained concurrency control,
involving techniques such as adaptive callbacks (discussed in Problems
14.6
and
14.7
). Jaluta [
2002
] and Jaluta et al. [
2006
]present
ARIES
-compatible algo-
rithms for the management of transactions in a page-server system, including
B-tree management with redo-only structure modifications, key-range locking, and
adaptive callbacks; a solution to Problem
14.7
can be found here.
