Oracle® Application Server Release Notes
10g (9.0.4) for Solaris Operating System (SPARC) Part No. B10629-15 |
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This chapter describes the issues associated with Oracle Application Server Web Cache (OracleAS Web Cache). It includes the following topics:
This section describes general issues and their workarounds for OracleAS Web Cache. It includes the following topics:
Section 16.1.2, "Compressed Content Not Displaying Correctly in Browsers"
Section 16.1.3, "Cookie and JavaScript in Pages Monitored by End-User Performance Monitoring"
Section 16.1.7, "Change in Behavior of Responses to Range Requests"
When you configure OracleAS Web Cache to cache Web pages other users can access these pages if they know the URLs. For this reason, do not create cache secure content.
When you enable compression, some browser bugs effect compression and the output HTML. You may have to perform additional configuration to use compression for certain browsers types, or you may have to disable compression for specific browsers with bugs.
See Also:
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End-user performance monitoring creates an additional cookie and inserts JavaScript into pages. The application may generate cookies and JavaScript that conflict with additional cookies and JavaScript created by End-User Performance Monitoring. If this behavior causes a problem for an application, then disable this feature in the End-User Performance Monitoring page (Logging and Diagnostics > End-User Performance Monitoring) of OracleAS Web Cache Manager.
Because OracleAS Web Cache is an in-memory cache, it is best to deploy OracleAS Web Cache on a dedicated computer to minimize paging. Unless the computer is dedicated to run OracleAS Web Cache, ensure the maximum cache size does not exceed 20 percent of the total memory.
If the time taken to cache or invalidate objects increases, check if the computer is paging. Paging can severely degrade performance. To configure OracleAS Web Cache to work efficiently on a computer with paging, either deploy OracleAS Web Cache on a dedicated computer or reduce the maximum cache size and maximum cached object size.
If OracleAS Web Cache uses more memory than the maximum cache size, the increase may be caused by numerous simultaneous requests for documents that are larger than the maximum cached object size. In this situation, because the documents are not cached, OracleAS Web Cache uses more memory processing the requests and forwarding them to the origin server than it would to cache the documents. Review access logs to determine if many simultaneous requests for large documents have been made and adjust the size of the maximum cached object size so that those documents are cached. In addition, check to be sure that a caching rule or response header specifies that the documents be cached.
To modify the maximum cache size or the maximum cached object size, set new limits for the Maximum Cache Size and Maximum Cached Object Size in the Resource Limits page (Properties > Resource Limits) of OracleAS Web Cache Manager.
See Also: Oracle Application Server Web Cache Administrator's Guide for more information about recommended topologies |
A system without enough disk space can cause OracleAS Web Cache to fail. Ensure there is sufficient space on the partition that contains the log files.
When OracleAS Web Cache is added to an existing application Web server environment, HTTP traffic changes effect the following aspects of the application:
Protocol/Hostname/Port Mapping
To ensure traffic is directed through OracleAS Web Cache, configure all absolute URLs to use the protocol, host name, and port number of OracleAS Web Cache. Also, ensure the Port
directive in the Oracle HTTP Server httpd.conf
file specifies the OracleAS Web Cache listening port.
SSL Processing
Add certificate management to OracleAS Web Cache, if the connection between the client and OracleAS Web Cache is HTTPS, but the connection between OracleAS Web Cache and the origin server is HTTP.
Page Delivery Timing
For compressed pages or pages that requires processing, OracleAS Web Cache waits for an entire page from the origin server before it sends it to the browser.
HTTP Protocol
OracleAS Web Cache transparently performs the following:
OracleAS Web Cache upgrades and downgrades the protocol version between the origin server and browser.
For cacheable objects, OracleAS Web Cache sends content to browsers with the Content-Length
response header instead of chunked encoding for the initial request.
For cache hits, OracleAS Web Cache overwrites the Content-Length
response-header field whenever it is different from what the origin server sent. This feature ensures browsers receive full page content.
In previous releases, when OracleAS Web Cache received a request for a multi-part document with an HTTP Range
request-header field and that document was not already cached, OracleAS Web Cache requested the entire document from the origin server and served it to the client. If the document was already cached, OracleAS Web Cache served only the part that the client requested.
In this release, when OracleAS Web Cache receives a request for a multi-part document with an HTTP Range
request-header field and that document is not already cached, OracleAS Web Cache now requests the partial document from the origin server. OracleAS Web Cache correctly returns the response (which could be an entire or partial document depending on what it received from the origin server) to the client.
However, OracleAS Web Cache caches only responses that are entire documents; it does not cache responses that are range responses. This caching behavior will be fixed in a future release.
This section describes configuration issues and their workarounds for OracleAS Web Cache. It includes the following topics:
Section 16.2.5, "Removing a Cache from a Cluster Before Running chgiphost.sh"
Section 16.2.6, "Sending Invalidation Requests Between Cache Cluster Members During Upgrade"
Section 16.2.7, "Binding Session Associated with Multiple Cookies"
Section 16.2.8, "Reloading Issue with Cache Operations Success Message in Internet Explorer Browser"
Use OracleAS Web Cache Manager to configure OracleAS Web Cache. Once configuration is complete, you can use the Application Server Control to start, stop, or restart the cache, as well as monitor cache and origin server status.
To use OracleAS Web Cache Manager:
If not currently logged on to the OracleAS Web Cache computer, log in with the user ID of the user that performed the installation.
Start OracleAS Web Cache with the Oracle Process Manager and Notification (OPMN) Server. From the command line, enter:
opmnctl startproc ias-component=WebCache
Point your browser to the OracleAS Web Cache Welcome URL:
http://
web_cache_hostname
:4000/webcacheadmin
When prompted for the administrator user ID and password, enter either the user name, ias_admin
, or the OracleAS Web Cache administrator user name, administrator
, for the user name. If you supplied a password during the installation, enter that password.
OracleAS Web Cache uses two configuration files: webcache.xml
and internal.xml
. The OracleAS Web Cache Manager writes its configuration information to the webcache.xml
file. OracleAS Web Cache uses internal.xml
file. These files are located in the $ORACLE_HOME/webcache
directory on UNIX and ORACLE_HOME
\webcache
directory on Windows. Do not edit these configuration files manually, except in the cases described in these Release Notes, or when directed to do so by Oracle Support Services. Improper editing of these configuration files may cause problems in OracleAS Web Cache.
See Also: Oracle Application Server Web Cache Administrator's Guide for complete configuration coverage |
Common configuration mistakes include:
Not mapping sites correctly to origin servers in the Site-to-Server Mapping page (Origin Servers, Sites, and Load Balancing > Site-to-Server Mapping). When sites are not mapped, OracleAS Web Cache directs requests to the default Oracle HTTP Server. Other site configuration errors include:
Not specifying all the site aliases
Misuse of the wildcard character *
Creating multiple site-to-server mappings for a site with multiple origin servers
Port conflicts
Ping URL
When configuring the Ping URL field in the Origin Server page (Origin Servers, Sites, and Load Balancing > Origin Servers), how you enter the URL depends on the origin server. For an application Web Server, enter either a relative or fully-qualified URL that includes the domain name, or site name, representing the virtual host of the application Web server. For a proxy server, enter a fully-qualified URL that includes the domain name, or site name, representing the virtual host of the origin server behind the proxy server. Ensure the URL is cached.
Running webcached
with root privilege
You must configure webcached
to run with root privilege when privileged port numbers less than 1024, there are more than 1,024 file descriptors, or the current opmnctl
or webcachectl
user does not match the configured user in the Process Identity page (Properties > Process Identity) of OracleAS Web Cache Manager.
See Also: Oracle Application Server Web Cache Administrator's Guide for complete configuration details |
By default, OracleAS Web Cache is configured to use the following default HTTP ports:
Listen requests: 7777
Administration requests: 4000
Invalidation requests: 4001
Statistics requests: 4002
If these ports are in use, then the installation procedure attempts to assign other port numbers from a range of possible port numbers.
At the end of installation, OracleAS Web Cache attempts to start. If there are port conflicts, then OracleAS Web Cache may fail to start.
See Also: Oracle Application Server Web Cache Administrator's Guide for more information about configuring ports, resolving port conflicts, and event log messages related to port conflicts |
To specify a maximum cached object size, go to the Resource Limits page (Properties > Resource Limits) of OracleAS Web Cache Manager.
If you specify a maximum cached object size, only documents that are not larger than a specified size and that match the caching rules will be stored in the cache. Objects larger than the specified size will not be cached, even if they meet other caching rules. The default is 100 KB for 9.0.4 installations. For upgraded caches, the default is that no limit is specified. If you want to apply the default to upgraded caches, modify the entry for Maximum Cached Object Size in the Resource Limits page.
If you have documents that are larger than the maximum cached object size and those documents are requested frequently, consider increasing the maximum cached object size limit.
The setting for the maximum cached object size is ignored if no Content-Length
header is present in the response.
See Also: Oracle Application Server Web Cache Administrator's Guide for more information about configuring resource limits |
The script chgiphost.sh
enables you to change the host name or IP address of a computer. If the computer contains a middle-tier instance that is part of OracleAS Web Cache cluster, remove the instance from the cache prior to running this script.
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If you have a OracleAS Web Cache cluster, you can upgrade one cache cluster member at a time. The caches will continue to respond to requests. However, because other cluster members have a different version of the configuration, the caches will not forward requests to those cache cluster members operating with a different version. Instead, if the requested document is not cached by that cache or by cluster members with the same version of the configuration, OracleAS Web Cache forwards the request to the origin server. In this situation, the Operations page (Operations > Cache Operations) in OracleAS Web Cache Manager indicates that the Operation Needed is Incompatible software version.
When the cache cluster members are not running the same version of OracleAS Web Cache, you can still invalidate documents and you can propagate the invalidation to other cluster members, but the invalidation request must originate with the cache that is operating with the earlier version, such as 9.0.2 or 9.0.3, of OracleAS Web Cache.
See Also: Oracle Application Server 10g Upgrading to 10g (9.0.4) for more information about upgrading OracleAS Web Cache to 10g (9.0.4), including information about upgrading cache cluster members |
To configure OracleAS Web Cache to bind user sessions to an origin server, you associate a site with a session definition name in the Session Binding page (Origin Servers, Sites, and Load Balancing > Session Binding) in OracleAS Web Cache Manager. If you want OracleAS Web Cache to bind user sessions with multiple cookies when any cookie is set, select a session of Any Set Cookie
. When selecting Any Set Cookie
, in Session Binding Cookie, click Enable to instruct OracleAS Web Cache to include a Set-Cookie
response-header in the response.
See Also: Oracle Application Server Web Cache Administrator's Guide for more information about configuring session binding settings |
When you submit a successful operation in the Cache Operations page (Operations > Cache Operations) in OracleAS Web Cache Manager, a Success message box appears. When you click OK to acknowledge the message, on some version of Internet Explorer, the Success dialog box reloads the OracleAS Web Cache Manager interface into the message box itself.
This section describes known errors in the documentation.
Chapter 8, "Specialized Configuration," in the Oracle Application Server Web Cache Administrator's Guide provides a procedure called "Running webcached with Root Privilege" that describes running webcached
as the root privileges for the following cases:
Privileged port numbers less than 1024 are being used for OracleAS Web Cache listening ports.
There are more than 1,024 file descriptors being used for connections to OracleAS Web Cache.
The current opmnctl
or webcachectl
user does not match the configured user in the Process Identity page (Properties > Process Identity) of OracleAS Web Cache Manager.
This procedure, which includes information for changing the process identity of the OracleAS Web Cache processes, is not accurate for the first two bulleted points. For privileged ports and to increase the file descriptor limit for OracleAS Web Cache, you can use the setroot
command of the webcache_setuser.sh
to provide OracleAS Web Cache with root privilege without requiring changing the process identity settings.
To provide OracleAS Web Cache with root privilege, perform the following as the root user:
The Oracle Application Server Web Cache Administrator's Guide and the online help for OracleAS Web Cache Manager does not describe the fact that a dummy wallet is located in $ORACLE_HOME/webcache/wallets/default
on UNIX and ORACLE_HOME
\webcache\wallets\default
on Windows. This wallet is intended for testing purposes for OracleAS Web Cache HTTPS communication to origin servers. For a production environment, use the procedures described in the documentation to create a new wallet with Oracle Wallet Manager. By default, Oracle Wallet Manager stores wallets in directory /etc/ORACLE/WALLETS/
user_name
on UNIX and %USERPROFILES%\ORACLE\WALLETS
on Windows.