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Why tuning and what is Granule unit
Introduction
As a DBA you,
are also responsible for detecting
performance problems of your organization�s
database. You need to know how to start
investigating a performance problem and then
solve it. Your job�s responsibilities
dictate that you should at least be informed
of the following basic fundamental subjects:
Hands-on
In
this exercise you will learn about the
GRANULE unit, and how to perform performance
tuning.
Performance
Tuning Steps
When your
clients complain about application
performance, you look at the problem with
the following sequence.
1- SQL Statement tuning,
2- Optimizing sorting Operations,
3- Memory Allocation.
a- Operating System Memory size,
b- Oracle allocated Memory size (SGA-System
Global Area),
4- I/O contentions,
5- Latches & Locks,
6- Network Load.
Granule Unit
Remember that
the SGA components are allocated and
de-allocated in units of contiguous memory
called Granule. So it is very important that
the amount of allocated memory must be a
product of the Granule size and an integer.
If the SGA is less than 128MB, then a
granule is 4MB. If the SGA is larger than
128MB, then a granule is 16MB.
The minimum number of granules allocated at
startup is: 1 for the buffer cache, 1 for
the shared pool, and 1 for the fixed SGA,
which includes redo buffers.
Questions:
Q: How do you
perform tuning on your database?
Q: What is a
Granule Unit?
Q: How does a
granule unit work in an increasing or
decreasing the database memory?
Q: When a
client complain about his/her application
performance, what are the list of steps you
go through?
Q: If the size
of your SGA is greater than 128M, what is
the size of your database granule unit?
Q: If the size
of your SGA is less than 128M, what is the
size of your database granule unit?
Q: What is the
minimum number of granules allocated to the
buffer cache, and the shared pool? |
