Database Reference
In-Depth Information
System malfunctions.
When the database system stops functioning because of
some type of malfunction of the operating system or the DBMS itself, the DBA
takes a core dump of the main memory and registers for determining the nature of
the problem. The dump is taken before restarting the database system.
Follow-up and coordination.
Typically for system malfunctions, the DBA has to
seek outside help from the vendors of the operating system and the DBMS. The
DBA sends the core dump to the outside vendors. He or she needs to follow up and
coordinate the problem resolution with the vendors.
Application of fixes.
Usually vendors of the operating system or the DBMS supply
code to fix or patch up the system malfunctions. The DBA applies the fixes under
appropriate conditions and tests the solutions.
Transaction failures.
Whenever any transaction does not execute successfully and
aborts, the DBA gets involved in determining the cause of the problem and finding
a resolution. Transactions abort for many reasons such as bad data, incorrect coding,
or some external conflict.
User support.
The DBA and other project team members provide support to the
users of the database system by providing clarifications, educating the users on data-
base concepts, and resolving any of their database problems. The DBA is part of
the user support loop.
MONITORING AND REVIEW
After deployment of the database system, in addition to performing routine main-
tenance tasks, the DBA continues to inspect system performance. The project team
continues to monitor how the new database system matches up with the require-
ments and stores the desired information content. The DBA constantly examines
the various factors that affect system performance. He or she needs to know the
growth trend and whether the database will be able to scale up. The DBA also
has to keep the database performing at an optimal level to process transactions
efficiently.
How can the DBA and other project team members assess performance levels
and be assured of providing for growth? Of course, they need information about
how well the database is operating and how smoothly could it accommodate growth.
They need statistics about current performance. They need to review various aspects
of the design and development of the database system.
Statistics are indicators whose values provide information on how the database
is operating. These indicators present growth trends. You will understand how well
the database server functions. You will gain insights into how well applications
perform in the new database environment.
How do you monitor and collect statistics about the database environment? Two
common methods apply to the collection process. Sampling methods and event-
driven methods are generally used. The sampling method measures specific aspects
of database activity at regular intervals. You can set the duration of the interval. For
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