Donald K. Burleson
A distributed database, as its name
implies, has its datafiles spread across several databases in
different locations. This may require that there be DBAs in these
distributed locations. The major consideration will be network
reliability. This is especially true when two-phase commit is used.
Under two-phase commit, if one of your distributed database nodes
goes down, you can’t update tables that undergo two-phase commit
with that node’s data.
According to the Oracle Distributed Database Administrators Guide
(Oracle Corporation, 2001) the DBA needs to consider the following
items in a distributed environment:
* The number of transactions posted from each location.
* The amount of data (portion of table) used by each node.
* The performance characteristics and reliability of the network.
* The speed of various nodes and the capacities of its disks.
* The criticality of success if a node or link is down.
* The need for referential integrity between tables.
A distributed database appears to the user to be one database, but
is in fact a collection of database tables in separate databases
spread across several locations. These databases are, of course, on
different computer systems that are connected by a network.
This is an
excerpt by Mike Ault’s book “Oracle
Administration & Management”. If you want more current Oracle tips
by Mike Ault, check out his new book “Mike
Ault’s Oracle Internals Monitoring & Tuning Scripts” or
Ault’s Oracle Scripts Download.
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