Release 8.0.5 for Windows NT
A64416-01
Library |
Product |
Contents |
Index |
| Oracle8
Enterprise Edition Getting Started
Release 8.0.5 for Windows NT A64416-01 |
|
This chapter describes how to monitor Oracle8 Enterprise
Edition.
Specific topics discussed are:
The following tools enable you to monitor your Oracle8 database:
Each tool is described in the following sections.
| Additional
Information:
See Oracle8 Tuning for general tuning information and your operating system documentation for additional information on Windows NT Performance Monitor results and optimizing database performance. |
Oracle8 Performance Monitor is a graphical tool for measuring
the performance of Oracle8 Enterprise Edition objects on a local server
or other servers on a network. This tool is the same in appearance and
operation as the Windows NT Performance Monitor, except it has been preloaded
with Oracle8 database performance elements.
On each computer, you can view the behavior of objects, such
as the buffer cache, data dictionary cache, data files, threads, and processes.
An object is a graphical representation of an element in your system.
Every element, resource, and device in your system can be represented as
an object.
There is a set of counters associated with each object. A
counter is a unit of measurement used by the Performance Monitor
to display activity. The type of activity the counter measures is dependent
upon the type of object.
Certain object types and their respective counters are present
on all systems. Other counters, such as application-specific counters (like
Server Manager), appear only if the computer is running the associated
software.
Each of these objects has an associated set of counters that
provide information about device usage, queue lengths, delays, and information
used to measure throughput and internal congestion.
To use Oracle8 Performance Monitor to monitor and analyze
Oracle8 database performance, you must first install Oracle8 Performance
Utility. The Oracle8 Performance Utility enables the Windows NT Performance
Monitor to monitor Oracle8 database objects.
When you install Oracle8 Performance Utility, values are
automatically set in the registry as described in Appendix
C, "Configuration Parameters and the Registry".
The Oracle8 Performance Monitor allows you to monitor only one database instance at a time. For this reason, the registry contains the following values:
|
Note: Oracle Corporation recommends setting the security level on each of these registry values. |
To use Oracle8 Performance Monitor for another database instance
on the same computer or a UNIX computer, change the values appropriately
in the registry. You can also monitor non-NT Oracle databases by changing
the Hostname registry value so it points to another computer specified
in the TNSNAMES.ORA file.
To access Oracle8 Performance Monitor:
Choose Start > Programs > Oracle for Windows NT - [HOME_NAME]
> Oracle8 Performance Monitor.
The Performance Monitor window appears with the Chart View:
The Oracle8 Performance Monitor has four views you can choose
from the View menu:
| Additional
Information:
For complete information about the four views, see your Windows NT documentation. |
For each view (Chart, Alert, Log, and Report), you can decide
on the objects you want to monitor and save those settings to a file. When
an object is chosen, it is assigned a counter, a color, and added to the
status bar at the bottom of Oracle8 Performance Monitor.
To add objects to a view:
The Add to (Chart, Alert, Log,
Report) dialog box appears.
Below is the Add to Chart dialog box. Note the corresponding dialog boxes for the other views are different.
Below are the elements of the Add to Chart dialog
box. The other views' dialog boxes have similar features.
The selections you have chosen to monitor are displayed.
All Oracle8 system resources that can be monitored through
Oracle8 Performance Monitor begin with Oracle8. These measures are
defined in ORACLE_HOME\DBS\ PERF80.ORA. The following table shows
the Oracle8 objects and their associated counters. For additional information
on these objects, see Oracle8 Tuning.
|
Note: You can only monitor one instance at a time using Oracle8 Performance Monitor on a given computer. |
| Object | Counter | Description |
|---|---|---|
|
Oracle8 Buffer Cache |
phyrds/gets % |
The percentage of phyrds/gets is calculated as a Miss ratio. If the Miss counter is higher than 30% to 40%, increase the number of buffers in the buffer cache to improve performance. To make the buffer cache larger, increase the value of the DB_BLOCK_BUFFERS initialization parameter. This value is not time-derived. |
|
Oracle8 Data Dictionary Cache |
getmisses/gets % |
The value of this counter must be less than 10 or 15% for frequently accessed data dictionary caches. If the ratio continues to increase above this threshold while your application is running, increase the amount of memory available to the data dictionary cache. To increase the memory available to the cache, increase the value of the initialization parameter SHARED_POOL_SIZE. (See Oracle8 Tuning for more detailed information on tuning memory allocation in the Oracle8 database.) This value is not time-derived. |
|
Oracle8 Data Files |
Disk contention occurs when multiple processes try to access the same disk simultaneously. There are many ways of reducing disk contention, depending on the results from monitoring disk activity. Some corrective actions include:
These values are time-derived. |
|
|
Oracle8 Redo Log Buffer |
redo log space requests |
The value of this counter must be near zero. If this value increments consistently, processes have had to wait for space in the redo log buffer. In this case, it may be necessary to increase the size of the redo log buffer. |
|
Oracle8 DBWR stats1 |
|
These counters are helpful in tuning the Buffer Cache. |
|
|
Buffers scanned/sec is the number of buffers the DBWR scanned per second. The buffers scanned are on the LRU list. |
|
|
|
LRU_scans/sec is the number of times the DBWR scanned the Least Recently Used buffer list per second. |
|
|
Oracle8 DBWR stats2 |
|
These counters are helpful in determining how much work the DBWR has been requested to perform. |
|
|
Timeouts/sec is the number of times the DBWR timed-out per second. The DBWR is on a three second timeout interval. If the DBWR has not been posted within a three second interval, it times out. |
|
|
|
Checkpoints/sec is the number of checkpoint messages processed by the database writer per second. Whenever a checkpoint occurs, the DBWR must be messaged (posted) to "write dirty buffers to disk". |
|
|
Oracle8 Dynamic Space Management |
recursive calls/sec |
Dynamic extension causes Oracle8 to execute SQL statements in addition to those SQL statements issued by user processes. These SQL statements are called recursive calls. If Oracle8 makes excessive recursive calls while an application is running, it may be necessary to determine the cause. Examine the recursive calls statistic through the dynamic performance table V$SYSSTAT. |
|
Oracle8 Free List |
free list waits/ requests % |
Contention for free lists is reflected by contention for free data blocks in the buffer cache. You can determine if contention for free lists is reducing performance by querying V$WAITSTAT. If the number of free list waits for free blocks is greater than 1% of the total number of requests, consider adding more free lists to reduce contention. |
|
Oracle8 Library Cache |
reloads/pins % |
The percentage of SQL statements, PL/SQL blocks, and object definitions that required reparsing. Total Reloads must be near zero. If the ratio of Reloads to Pins is greater than 1%, then reduce the library cache misses. This value is not time-derived. |
|
Oracle8 Sorts |
The default sort area size is adequate to hold all the data for most sorts. However, if your application often performs large sorts on data that does not fit into the sort area, then you may want to increase the sort area size. |
If no data or Oracle8 objects appear in the Objects list of the Add to Chart dialog box, either:
The OPERF80.LOG file located in ORACLE_HOME\DBS contains
error messages about Oracle8 Performance Monitor.
To resolve this problem:
Oracle8 Enterprise Edition problems and other significant
occurrences are recorded as events. These events are recorded in an application
event log. View and manage these recorded events in the Event Viewer.
To access the Event Viewer:
The Event Viewer window appears.
The icons beside each event determine the type of event.
Oracle8 Enterprise Edition events display with a source of
Oracle80.orcl. Oracle80.orcl consists of the following event IDs:
To use the Event Viewer:
The Event Detail dialog box appears with more information about the selected event:
| Additional
Information:
See your Microsoft Windows NT documentation for more information on using the Windows NT Event Viewer. |
Setting AUDIT_TRIAL to DB or OS causes more records to be
written to the Event Viewer. This can fill up the Event Viewer log file.
Follow these procedures to increase the log file size.
To increase log file size:
The Event Log Settings dialog box appears.
You are returned to the Event Viewer.
Oracle8 Enterprise Edition background threads use trace files
to record occurrences and exceptions of database operations, as well as
errors. Background thread trace files are created regardless of whether
the BACKGROUND_DUMP_DEST parameter is set in the INITSID.ORA initialization
parameter file. If BACKGROUND_DUMP_DEST is set, the trace files are stored
in the directory specified. If the parameter is not set, the trace files
are stored in the ORACLE_HOME\RDBMS80\TRACE directory.
Oracle8 database creates a different trace file for each background thread. The name of the trace file contains the name of the background thread, followed by the extension .TRC. Sample trace file syntax includes:
where SID represents the name of the instance.
Trace files are also created for user threads if the USER_DUMP_DEST
parameter is set in the initialization parameter file. The trace files
for the user threads have the form ORAxxxxx.TRC, where xxxxx
is a 5-digit number indicating the Windows NT thread ID.
The alert file contains important information about error
messages and exceptions that occur during database operations. Each Oracle8
Enterprise Edition instance has one alert file; information is appended
to the file each time you start the instance. All threads can write to
the alert file.
For example, when automatic archiving of redo logs is halted
because no disk space is available, a message is placed in the alert file.
The alert file is the first place to check if something goes wrong with
the database and the cause is not immediately obvious.
The alert file is named SIDALRT.LOG and is found in
the directory specified by the BACKGROUND_DUMP_DEST parameter in the INITSID.ORA
initialization parameter file. If the BACKGROUND_DUMP_DEST parameter is
not set, the SIDALRT.LOG file is generated in ORACLE_HOME\RDBMS80\TRACE.
Oracle Corporation offers three optional performance management packs that are integrated into Oracle Enterprise Manager:
The three packs together offer a powerful set of tools for
monitoring performance, analyzing performance findings, and implementing
improvements in your Oracle8 database environment. These packs are not
on your Oracle8 Enterprise Edition for Windows NT CD-ROM. They must be
purchased separately.
Oracle Diagnostics Pack consists of the following tools:
Oracle Performance Manager is a tool for monitoring database performance in real time. It provides dozens of predefined charts for displaying a wide variety of database performance statistics regarding:
|
|
| Additional
Information:
See Oracle Enterprise Manager Performance Monitoring and Planning Guide for specific information on using this tool. |
Oracle Capacity Planner provides you with a comprehensive set of database and operating system statistics that can be collected. These collections are completely customizable, enabling you to select any set of statistics to collect and the interval at which they can be sampled.
| Additional
Information:
See Oracle Enterprise Manager Performance Monitoring and Planning Guide for specific information on using this tool. |
Oracle Advanced Events enables you to automatically monitor and detect problems on remote servers that may not be accessible from a graphical monitor. Oracle Advanced Events features include autonomous database and node monitoring, user-defined event threshold and monitoring intervals, user-defined event sets, multifaceted event notification, and automated problem correction.
| Additional
Information:
See Oracle Enterprise Manager Performance Monitoring and Planning Guide for specific information on using this tool. |
Oracle TopSessions enables you to monitor how connected sessions
use database instance resources in real time. You can obtain an overview
of session activity by displaying the top n sessions sorted by a
statistic of your choice. For any given session, you can drill down for
more detail. You can further customize the information you display by specifying
manual or automatic data refresh, the rate of automatic refresh, and the
number of sessions to display.
In addition to these monitoring capabilities, Oracle TopSessions provides a methodology for identifying and correcting certain database performance problems. For example, when a sudden file I/O load is detected, you can first identify the sessions contributing to most of the problem, and then isolate the executing SQL statements in user applications for those sessions. You can then analyze the SQL explain plans for those SQL statements to determine how best to resolve the problem.
Oracle Lock Manager enables you to monitor locks, which are
mechanisms that prevent destructive interaction between users accessing
the same resource.
The main window displays a multi-column list that includes a row for each current lock in the database. The information displayed in the columns includes:
Oracle Trace is a general-purpose data collection product
that captures data for specific software events, such as an application
transaction, a user log on, or any event particular to the software product.
With Oracle Trace, you can collect a wide variety of data, such as performance
statistics, diagnostics data, system resource usage, and business transaction
details.
Two Oracle Corporation products are currently enabled for Oracle Trace collection:
The Oracle8 Enterprise Edition performance data collected
by Oracle Trace includes SQL statements, detailed statistics on SQL events,
transactions events, and other useful information.
Oracle Trace provides a graphical Oracle Trace Manager application
to create, schedule, and administer Oracle Trace collections for host products
containing the Oracle Trace application programming interface (API). You
can store data collected by Oracle Trace in Oracle8 database tables for
access by SQL reporting tools and other products.
Oracle Trace has an API that contains data collection service
calls. Software developers can use the Oracle Trace API to pre-configure
their products for Oracle Trace data collection. Users of a product containing
the Oracle Trace API calls, such as the Oracle8 database, can then automatically
use Oracle Trace to collect data about specific events that occur in that
product.
Most Oracle Trace users perform collections for products
that already include the Oracle Trace API. Therefore, most users only need
to be familiar with the data that can be collected for the host product
and how to use the Oracle Trace Collection Manager application to create
and administer data collections.
| Additional
Information:
See Oracle Enterprise Manager Oracle Trace User's Guide for specific information on using this tool. |
Oracle Tuning Pack consists of the following tools:
Oracle Tablespace Manager enables you to monitor and manage
tablespace fragmentation. You can display an overview of table space usage
information, either for all tablespaces in a database, or for the data
file(s) within a tablespace.
To find out more about a given tablespace or data file, you can display how storage has been allocated for its segments. Clicking a segment in a segment list displays the extents in the tablespace or data file storing data for that segment. If data storage for a segment is fragmented, you can defragment it. You can also use the coalescing feature of Oracle Tablespace Manager to join adjacent free blocks.
Oracle SQL Analyze examines your database SQL workload to determine which statements significantly impact performance. Data for all open cursors is captured and evaluated dynamically based upon user-selected criteria, such as resource usage and I/Os per statement. Extensive details are provided for examining SQL statements, including:
| Additional
Information:
See Oracle Enterprise Manager Getting Started with Oracle SQL Analyze for specific information on using this tool. |
Oracle Expert enables you to optimize the performance of your database environment. It assists you with the initial Oracle8 database configuration and the collection and evaluation of the performance characteristics of existing databases. Oracle Expert provides many advantages. Oracle Expert:
Oracle Expert also serves as:
| Additional
Information:
See Oracle Enterprise Manager Oracle Expert User's Guide for specific information on using this tool. |
The Oracle Change Management Pack consists of six applications:
These applications allow you to make complex changes to schema objects (like dropping a column from a table), track changes to schemas and databases over time, make copies of schemas or objects, and compare and synchronize schemas and databases.
| Additional
Information:
See Oracle Enterprise Manager Getting Started with Oracle Change Management Pack for specific information on using this tool. |
