Hi,
I have an automated test of a web services application running on
Tomcat (6.0.18) behind Apache (2.2.11) We use mod_jk (1.2.27)
Our test suite runs a client against the Apache server on a system
where we have a single Tomcat instance behind Apache.
So far so good, all test passed.
Now, I tried using Apache as a load balancer; using two Tomcat
instances behind Apache.
All of my tests passed, except for one that failed on a strange way.
The test does the following:
deleteAllItems
createItem (A)
createItem (B)
createItem (C)
list = getAllItems()
at this point we verify that we get 3 items on the list, but instead
of 3, the list returned 4 items!!
This was the only test that failed from a test suite of about 400. I
ran the same test suite again and the error did not occur again.
So, could it be related to the configuration of the mod_jk module in
Apache?
Currently we don't specify the "recovery_options" for the Tomcat
worker (therefore it defaults to "0") in workers.properties.
We do not specify the "retries" either, so it defaults to "2".
I was wondering if in the test above, a "createItem" call was resent
to a Tomcat instance due to some communication error, and therefore 4
items were created in the database instead of the 3 we expected.
I would appreciate if someone could shed more light on the
"recovery_options" from what it is found in the documentation.
Below is what I found on the documentation
http://tomcat.apache.org/connectors-doc/reference/workers.html#Advanced%
20Worker%20Directives
Thanks a lot.
-Jorge
------------------
recovery_options
------------------
Worker Type: AJP,SUB
Default value: 0
Recovery options influence, how we should handle retries, in case we
detect a problem with Tomcat. How often we will retry is controlled by
the attribute retries.
This attribute is a bit mask. The following bits are allowed:
1: don't recover if Tomcat failed after getting the request
2: don't recover if Tomcat failed after sending the headers to client
4: close the connection to Tomcat, if we detect an error when writing
back the answer to the client (browser)
8: always recover requests for HTTP method HEAD (even if Bits 1 or 2 are
set)
16: always recover requests for HTTP method GET (even if Bits 1 or 2 are
set)
This features has been added in jk 1.2.6. Option 4 has been added in
version 1.2.16, options 8 and 16 in version 1.2.24.
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