Oracle Database Cache Concepts and Administration Guide Release 1.0.2.1 Part Number A88706-01 |
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This chapter describes error logging, cautions against certain actions, describes some problems you may encounter in your Oracle Database Cache environment and solutions to those problems, and notes restrictions to the software.
To help you troubleshoot problems in your environment, Oracle Database Cache writes error messages to a log file or an event viewer.
By default, on UNIX, the file specification of the log file is:
$ORACLE_HOME/admin/icache/bdump/wtcme.log
On Windows NT, Oracle Database Cache writes error messages to the Event Viewer. From the Windows NT Start menu, select Programs -> Administrative Tools -> Event Viewer. From the Log menu of the Event Viewer, choose Application. Then, select events named OracleWtcIcache.sid, where sid is the Oracle system identifier (SID) of the cache.
If error messages cannot be written to the event log, errors are written to the log file:
ORACLE_HOME\admin\icache\bdump\wtcme.log
Note that the contents of the log file are always written using the UTF8 character set. If the log file contains non-ASCII characters, you may need to use a text viewer that can display characters in the UTF8 character set.
You can change the level of errors written to the log file and, on UNIX, the name and location of the log file. To make these changes, modify the parameters in the file wtcme.ora
or specify a parameter to the wtcme
command.
The file wtcme.ora
is located in the following directory:
The following table describes the parameters that are specified in the wtcme.ora file:
Parameter | Description |
---|---|
authenticationserver |
The tnsname of the origin database. Do not use the command line or edit the file to change this parameter. The tnsname is set during installation. |
port |
The port number of the listener for Oracle Database Cache. The listener establishes a communication path between Oracle Database Cache on the middle tier and Cache Manager on the client tier. Do not use the command line or edit the file to change this parameter. The port number is set during installation or by using the Configuration Assistant as described in "Using the Configuration Assistant to Reconfigure a Cache". By default, the port number is 51719. |
logfile |
The full file specification for the log file. By default, the value is set to the following: |
loglevel |
The level of error messages written to the log file wtcme.log or to the Windows NT Event Viewer. Valid values are:
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The following command specifies a log level of debug:
wtcme loglevel=debug
The following describes some important information that can help you to prevent problems and fix problems if they occur:
ORACACHE
is created.
ORACACHE$n
In the format, n represents an integer between 1 and 1000.
Do not delete these users from the origin database or change their passwords.
Do not modify or delete these objects.
If the port number used by Oracle Database Cache is the same number as an existing port, the Configuration Assistant does not return an error during installation. It writes a message to the installation log indicating that the listener is already started.
However, when you attempt to access the cache using the listener (as when clients are routed to the cache), you receive the following error:
ORA-12541 - TNS: no listener
To resolve the problem, edit the listener.ora and tnsnames.ora files and specify a port number that is not used.
If you modified or deleted the entries that Oracle Database Cache placed in the tnsnames.ora file on the cache node, Oracle Database Cache will not operate correctly. Edit the tnsnames.ora file to match the following entries:
# Name for the cache. ora_icache = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = IPC)(KEY = <your_dbSid>)) ) (CONNECT_DATA = (SERVICE_NAME = <HostName-GlobaldbName>) ) )
# Oracle Database Cache's origin database ora_icache_origin = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP) (HOST = <originHostName>) (PORT = <originPortNumber>)) ) (CONNECT_DATA =(SERVICE_NAME = <originServiceName>) ) )
# Support for external procedures within Oracle Database Cache extproc_connection_data = (DESCRIPTION = (ADDRESS = (PROTOCOL = ipc)(KEY = <your_dbSid>) ) (CONNECT_DATA = (SID = iCache_extproc) (SERVER = DEDICATED) ) )
<HostName-GlobaldbName> = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = IPC) (KEY = <your_dbSid>)) ) (CONNECT_DATA = (SERVICE_NAME = <HostName-GlobaldbName>) ) )
# Support for mod_ose over normal TCP connections inst1_http = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP) (HOST = <hostName>) (PORT = 1521) ) (CONNECT_DATA = (SERVICE_NAME = MODOSE) (SERVER = shared) (PRESENTATION = http://admin) ) ) # To support mod_ose over TCP with SSL connections, remove the comments # from the following entry: #inst1_https = # (DESCRIPTION = # (ADDRESS = # (PROTOCOL = TCPS) # (HOST = %s_hostName%) # (PORT = 2484) # ) # (CONNECT_DATA = # (SERVICE_NAME = MODOSE) # (SERVER = shared) # (PRESENTATION = http://admin) # ) # )
If you modified or deleted the entries that Oracle Database Cache placed in the listener.ora file on the cache node, Oracle Database Cache will not operate correctly. Edit the listener.ora file to match the following entries:
CONNECT_TIMEOUT_LISTENER = 0 LOGGING_LISTENER = OFF LISTENER = (DESCRIPTION_LIST = (DESCRIPTION = # Local connections (ADDRESS_LIST = (ADDRESS = (PROTOCOL = IPC)(KEY = <your_dbSid>)) ) ) (DESCRIPTION = # General TCP connections (ADDRESS = (PROTOCOL = TCP)(HOST = <hostName>)(PORT = 1521)) ) # For secure connections over SSL, remove the comment characters # from the following entry: # (DESCRIPTION = # Secure TCP connections # (ADDRESS = # (PROTOCOL = TCPS)(HOST = <hostName>)(PORT = 2484)) # ) (DESCRIPTION = # IIOP connections (PROTOCOL_STACK = (PRESENTATION = GIOP) (SESSION = RAW)) (ADDRESS = (PROTOCOL = TCP)(HOST = <hostName>)(PORT = 2481)) ) # For secure IIOP connections over SSL, remove the comment characters # from the following entry: # (DESCRIPTION = # Secure IIOP connections # (PROTOCOL_STACK = (PRESENTATION = GIOP)(SESSION = RAW)) # (ADDRESS = (PROTOCOL = TCPS)(HOST = <hostName>)(PORT = 2482)) # ) ) SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (GLOBAL_DBNAME = <hostName>-<globalDBName>) (ORACLE_HOME = <ORACLE_HOME>) (SID_NAME = <your_dbSid>) ) (SID_DESC = (ORACLE_HOME = <ORACLE_HOME>) (SID_NAME = iCache_extproc) (PROGRAM = extproc) ) )
To use all features of the Oracle Database Cache product, Oracle Database Cache, the Oracle Database Cache management engine, Oracle Data Gatherer, and TNS Listener must be started.
To use Cache Manager to manage your caches, the Oracle Database Cache management engine must be started. When the management engine is not started on a middle-tier node, Cache Manager cannot access the cache. Cache Manager displays the General page for that cache as dimmed.
If Oracle Data Gatherer and TNS Listener are not started, you will not be able to use Oracle Database Cache or some functionality of the product.
On UNIX systems, if you followed the procedures for automating startup and shutdown in the installation guide, Oracle Database Cache (as well as the Oracle Database Cache management engine, Oracle Data Gatherer, and TNS Listener) is started when your system starts.
On Windows NT systems, Oracle Database Cache, the Oracle Database Cache management engine, and TNS Listener are services that are started automatically when your system starts.
On UNIX, if Oracle Database Cache is stopped, you can restart it, the Oracle Database Cache management engine, Oracle Data Gatherer, and TNS Listener by executing the cachstrt
script, which is located in the $ORACLE_HOME/bin directory. Use the following command:
cachstrt
On UNIX, to stop Oracle Database Cache and the TNS Listener, execute the cachshut
script, which is located in the $ORACLE_HOME/bin directory:
cachshut
To execute these commands, you must be logged in as the user under which Oracle Database Cache was installed.
On Windows NT, if Oracle Database Cache is stopped, you can restart it by starting the service:
On Windows NT, you must start the Oracle Database Cache management engine separately:
To start the Data Gatherer and the TNS Listener, see the following sections.
Oracle Data Gatherer, which manages the collection of statistics for use by Oracle Enterprise Manager components such as DBA Studio, must be started on the middle-tier machine. If it is not, you may receive the following error when you click on the Performance Monitor tab for a cache:
Cannot connect to Data Gatherer for cache. Some performance charts will not be available.
On UNIX, use the following command to start Oracle Data Gatherer:
vppcntl -start
On Windows NT, take these steps to start Oracle Data Gatherer:
TNS Listener must be started on the middle-tier node. If it is not, queries are routed to the origin database.
Note that the listener on the middle-tier node is configured to listen for IPC protocol connection requests. The IPC protocol is used by applications that reside on the same node as the listener to communicate with a cache.
On UNIX, use the following command to start the listener:
lsnrctl start listener
On Windows NT, take these steps to start the listener:
Oracle Database Cache uses threads to monitor and maintain statistics about the behavior of the cache. As a result, if an application already uses OCI in threaded mode, you do not need to make any changes to the application. If the application is a single-threaded application, you must relink the application using the multithreaded mode.
For example, on UNIX, you use the -lthread
option in the link line.
On Windows NT, you link with the msvcrt.lib library.
If the application is not linked in multithreaded mode, Oracle Database Cache may not execute properly and may return errors, such as the following error:
Failed: Register Aggregate Stats Queue
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