Latency messages in DataPower appliance

Technote (FAQ)


Question

Here are two examples of WebSphere DataPower latency messages:

Mon Sep 19 2011 13:23:40 [latency][info] xmlfirewall (loopback-fw): tid(2809): Latency: 0 1 0 1 1 0 0 1 1 1 1 1 0 0 1 1 [http://<IP address>:9999/foo/test.xml]

Fri Feb 16 2012 13:04:27 [latency][info] xmlfirewall(TestLogging): tid(2075615): Latency: 0 0 0 0 1 0 0 1 0 0 0 1 0 0 0 0 [http://127.0.0.1:9999/]

What are each of the latency arguments in this message?

Answer

These Latency arguments are the timestamps marking when certain events occurred during the life of a completed HTTP transaction.
Each timestamp is expressed in milliseconds (ms) since the transaction began (not additive).

A '0' means that event did not occur and streaming processing can cause the order to change depending on the configuration.

The values reflect the following events respectively: The latencies measure in milliseconds the time since a base latency measurement was taken. Usually, this is at the start of the HTTP transaction.

Please note that the following latency log format is the same for all types of services on DataPower.

The latency log format (numbers are in milliseconds):

Explanation of Arguments found in the Latency log message
Position Argument
1 request header read
2 request header sent
3 front side transform begun
4 front side transform complete
5 entire request transmitted
6 front side style-sheet ready
7 front side parsing complete
8 response header received
9 response headers sent
10 back side transform begun
11 back side transform complete
12 response transmitted
13 back side style-sheet read
14 back side parsing complete
15 back side connection attempted
16 back side connection completed

Since the arguments above are not additive and mark the timestamps of different events that are not necessarily in order of the transaction execution, it may be useful to understand the "real" order of execution.

The following table shows the execution order of the events in the order they would typically occur during a transaction:
The "real" execution order of the Latency Arguments for a transaction
Position Argument
1 request header read
3 front side transform begun
7 front side parsing complete
6 front side style-sheet ready
4 front side transform complete
15 back side connection attempted
16 back side connection completed
2 request header sent
5 entire request transmitted
8 response headers received
10 back side transform begun
14 back side parsing complete
13 back side style-sheet read
11 back side transform complete
9 response headers sent
12 response transmitted

There are some variables that may be used for access to certain latency data:
Names and permissions for variables that are available for latency
Variable name Permission
var://service/time-elapsed Read-only
var://service/time-forwarded Read-only
var://service/time-response-complete Read-only
var://service/time-started Read-only

See the Product Documentation Portal for more information about this subject.

Rate this page:

(0 users)Average rating

Document information


More support for:

IBM DataPower Gateways
General

Software version:

4.0.2, 5.0.0, 6.0.0, 6.0.1

Operating system(s):

Firmware

Software edition:

Edition Independent

Reference #:

1239328

Modified date:

2007-03-01

Translate my page

Machine Translation

Content navigation