Web Cache Error

Question

We are occassionally getting the following error in various scenarios -- in development or just browsing the site:
"Oracle Web Cache Network Error"
Oracle Web Cache encountered a network error when communicating with the application web server.
We have Web Cache installed on the same server as the portal application, but an Oracle consultant who was in a few weeks ago said we had more than enough capacity. Any ideas? We're on Oracle Portal Version: 3.0.9.8.2 and

Answer 1

The error you are seeing is usually the result of a slow response from your origin server, although it could be something else. If you provide
a snippet of your Web Cache event log (verbose), I'll be able to assist you better.
For now, let's assume it is due to a slow origin server response. On a cache miss, if the Web Cache doesn't receive a response
from the origin server within a given time interval, it will close the connection with the origin server and respond to the browser with
a network apology page. This is the page you are seeing. There are ways to correct this.
First of all, you should modify the network apology page in order to customize it for your application or web site. The file is located in the $ORACLE_HOME/webcache/docs directory.
If you're using Web Cache 9.0.2.x, the default origin server timeout is 3600 seconds. You probably won't have to change this, but if you want to, then
please refer to the "Oracle9iAS Web Cache v9.0.2.0 Administration and Deployment Guide", available on OTN.
The relevant section is" Chapter 6, Task 7: Configure Network Timeouts."
If you're running Web Cache 2.0.0.x, the default origin server response timeout is 30 seconds. This default was chosen because we felt
that no application should take more than 30 seconds to respond to a user's request. Since then, we've learned that a lot of apps out there,
especially business intelligence apps, have complex queries that take several minutes, if not hours, to complete. To change this default timeout, you need to modify your internal.xml
file. Here's a snippet from the 2.0.0.4 readme.html file describing how to do this:
3.0 Network Apology Pages
When Oracle Web Cache sends requests to an application Web server, Oracle Web Cache permits the application Web server 30 seconds in which to
generate a response for the browser. If the application is unable to generate a response within that time, Oracle Web Cache sends a network apology
page to the browser.
If 30 seconds is not sufficient, then you can change the default settings of the OSSEND_TIMEOUT and OSRECV_TIMEOUT attributes in the
internal.xml file:
OSSEND_TIMEOUT: Network round-trip time (latency) between Oracle Web Cache and the application Web server. The 20 second default of
the OSSEND_TIMEOUT attribute is usually sufficient for most operating systems.
You can determine the latency to the application Web server by issuing the the following command from the Oracle Web Cache computer:
ping -s application_Web_server
This command provides output similar to the following:
PING sales.us.acme.com: 56 data bytes
64 bytes from sales.us.acme.com (130.35.45.34): icmp_seq=0. time=20. ms
64 bytes from sales.us.acme.com (130.35.45.34): icmp_seq=0. time=21. ms
If the time value is over 20 seconds, then increase the OSSEND_TIMEOUT attribute value.
OSRECV_TIMEOUT: Latency and application Web server processing time. The default is 30 seconds.
You can determine the processing time by sending a sample request to the application Web server and monitoring the time to process the
request. If the processing time is over 30 seconds, then increase the OSRECV_TIMEOUT attribute value.
To change these default settings:
1.Locate the following line in the internal.xml file:
<CALYPSONETINFO/>
2.Modify the <CALYPSONETINFO/> line as follows:
Add the OSSEND_TIMEOUT attribute as follows:
<CALYPSONETINFO OSSEND_TIMEOUT="seconds"/>
Add the OSSRECV_TIMEOUT attribute as follows:
<CALYPSONETINFO OSSRECV_TIMEOUT="seconds"/>
Add both the OSSEND_TIMEOUT and OSSRECV_TIMEOUT attributes as follows:
<CALYPSONETINFO OSSEND_TIMEOUT="time" OSRECV_TIMEOUT="time"/>