Databases Reference
In-Depth Information
How it works...
The database writes information on the alert log about log switches and checkpoints.
We can inspect the alert log to diagnose a possible problem with log files.
There's more...
We can force a log switch by using the following command:
ALTER SYSTEM SWITCH LOGFILE;
A checkpoint can be forced by using the following statement:
ALTER SYSTEM CHECKPOINT;
See also
F
We will see the use of
SQL_TRACE
and
TKPROF
to generate trace files and
the corresponding report over SQL activity of a particular session in
Tracing
SQL activity with SQL Trace and TKPROF
in
Chapter 4, Optimizing SQL Code
Analyzing data using Automatic Workload
Repository (AWR)
With Oracle Database 10
g
, Automatic Workload Repository (AWR) was introduced. It is a
tool that extends the key concepts of Statspack.
In this recipe, we will create a manual snapshot, a baseline, and some reports.
Getting ready
To use AWR, the
STATISTICS_LEVEL
parameter of the
init.ora
file must be set to the
value
TYPICAL
or
ALL
.
With the default setting
TYPICAL
, all the statistics needed for
self-management functionalities are collected, providing best
overall performance. Using the parameter
ALL
the database
will collect all the statistics included in the
TYPICAL
settings,
as well as timed operating system statistics and row source
execution statistics.
