Posted by Pieter Ennes on March 11th, 2010
At the same time that we were working on some improvements for Apache JMeter, Simon from BadBoy Software has kindly made available a pre-release of his software that, next to many other improvements, particularly supports exporting scripts that use Variable Setter elements to JMeter using functionality from JMeter’s similar Regular Expression Extractor. This is relevant in cases where your application exposes its session ID via the web page body, for example in a (hidden) form element instead of using a cookie. This release will make the process of recording and uploading scripts directly from BadBoy much easier, which is terrific as we recommend BadBoy as a primary tool to record our script monitors. We’ve already got one customer using this enhancement!
The preview can be downloaded from: BadboyInstaller-2.1_beta_8_pre_1_wm.exe
On a related track: We’ve added a small island on our main dashboard reminding our scripting customers that if they use BadBoy to record and upload scripts in their WatchMouse account, they are in fact entitled to a free licence for BadBoy!
Thanks for the patch Simon!
Posted by Pieter Ennes on March 10th, 2010
I’m very happy to be able to publish another patch, this time for Apache’s Jakarta JMeter that adds two new metrics (a connect time and processing time) to all output channels. To cut right to the chase, this is how it looks:
Displayed is the breakdown of a typical HTTP redirect scenario, from google.com to google.co.uk in this case, in the JMeter GUI. Shown in the right pane, are the timings of the selected parent element, summarising both the initial 302 as well as the 200 response from the server. The original Latency and Load time metrics are shown, and in yellow the stuff that I’ve added.
Connect time
This one simply measures the TCP connect time in HTTP samplers, including any host name lookups that may have to be done. So the printed time indicates the amount of time between the start of the test and the socket being ready. In case of a redirect (as above), the connect times to the individual hosts (google.com and google.co.uk) are summed into the parent element to indicate the total connect time that was involved.
Processing time
The processing time is defined as the time-to-first byte just as the latency. But in contrast to the latency, the processing time from sub-requests is summed into the parent element, just like the connect time, page load time and page size.
Having both these numbers available can allow better analysis of a performance problem. For example: If the connect time stays the same but the processing time goes up, this may indicate a CPU-related problem on the server and not a network or DNS issue. But there are many other situations where a breakdown like this may help with performance research.
Resolve time
Another performance metric that is missing in JMeter is the DNS resolve time. We are currently looking for a way to measure this, but I expect to be able to include it in the next version of the patch. Having resolve time available as well, will allow for even better analysis of a problem.
Feedback
At WatchMouse we use JMeter as a back-end for our functional monitors, and we are interested in these extra measurements to give our users a more detailed performance breakdown of their transactions. After deployment to our monitoring network we will start integration with our performance charts and Root Cause Analysis pages.
As always, we’re keen on your feedback regarding this patch! What’s your opinion on the definitions of these metrics? What else would you like to know regarding the performance of your scripts? And how would you like to see this information come back in our dashboard?
Pieter Ennes
WatchMouse
References
Posted by mark on February 11th, 2010
If you are considering a cloud infrastructure, your first questions should be: Does it exist? Does it scale? With the WatchMouse network of monitoring stations, I did some research over the past year into the computing clouds to shed some light on these basic questions.
We looked at the uptime of a number of cloud providers, such as Amazon, Akamai, and Google AppEngine. The results are in the following figure. What we see is that cloud uptime is pretty good, and it is getting better. As a matter of fact, these clouds perform better than a lot of commercial websites.
Another interesting question is: where is the cloud? We looked at the distance from the WatchMouse monitoring stations to a Google App Engine application. The following figure shows that the App Engine cloud is in fact spread out around the world!
On the vertical axis we see a number of WatchMouse monitoring stations, so that each horizontal bar represents the connect time from that station to either a regular website in the Netherlands, or an application at Google Apps Engine. From the graph it is clear that that cloud is in more than one place on the globe. Given the programming model of Google Apps Engine, this means that it is very scalable. Our research also shows that this cloud is expanding. For a more in-depth discussion of this data go to the slidecast (slides plus audio) of my presentation at the 2009 Computer Measurement Group conference.
So if you still thought that clouds are a foggy notion, this research is a wake-up call. Clouds do exist, are scalable and are getting better.
This is a guest column by Peter van Eijk, owner of Digital Infrastructures, a consultancy firm. He publishes a blog at http://petersgriddle.net and is currently setting up the Computer Measurement Group’s Dutch chapter. If you speak Dutch, follow the blog and join the NLCMG LinkedIn group. Contact information is listed on LinkedIn and on www.digitalinfrastructures.nl/contact
Posted by Pieter Ennes on October 19th, 2009
Update: Post updated for v0.2…
Hi folks,
While our own migration to IPv6-enabled monitoring is progressing nicely, we are making available our version of some rudimentary MySQL User Defined Functions (UDF’s) that allow you to work with IPv6 addresses in pre-6.0 versions of MySQL.
The currently implemented functions are inet6_pton() and inet6_ntop() to convert IPv6 (and IPv4) addresses between presentation and numeric (or binary) form directly in SQL. The former function converts a readable IP address string to a binary representation of either 4 bytes (IPv4) or 16 bytes (IPv6) long. The latter function does exactly the opposite, as shown in:
mysql> select inet6_ntop(inet6_pton('2001:4860:a005::68'));
+----------------------------------------------+
| inet6_ntop(inet6_pton('2001:4860:a005::68')) |
+----------------------------------------------+
| 2001:4860:a005::68 |
+----------------------------------------------+
1 row in set (0.00 sec)
mysql> select inet6_ntop(inet6_pton('1.2.3.4'));
+-----------------------------------+
| inet6_ntop(inet6_pton('1.2.3.4')) |
+-----------------------------------+
| 1.2.3.4 |
+-----------------------------------+
1 row in set (0.00 sec)
mysql> select
length(inet6_pton('1.2.3.4')) as ipv4len,
length(inet6_pton('2001:4860:a005::68')) as ipv6len;
+---------+---------+
| ipv4len | ipv6len |
+---------+---------+
| 4 | 16 |
+---------+---------+
1 row in set (0.00 sec)
You can neatly store the output of inet6_pton() in a VARBINARY(16) column (using a VARCHAR(16) would not be wise because because of possible character set conversion problems).
Of course, there are many ways one could store IPv6 addresses in a database, but the method described here seems to work best for us and is unlikely to conflict with any native support for IPv6 that MySQL will implement in future versions. Furthermore, the binary notation seems to work nicely with ranges, so you can use WHERE ip BETWEEN a AND b to do something like:
mysql> select * from log
where ip between inet6_pton('2001:db8::') and inet6_pton('2001:db9::');
to get all IP addresses in the 2001:db8::/32 range.
We’ve also included two address lookup functions that are IPv6 compatible:
mysql> select inet6_lookup('www.watchmouse.com');
+------------------------------------+
| inet6_lookup('www.watchmouse.com') |
+------------------------------------+
| 2001:1938:80:73::2 |
+------------------------------------+
1 row in set (2.08 sec)
mysql> select inet6_rlookup('2a02:f8::ffff:ffe5'), inet6_rlookup('64.128.190.61');
+-------------------------------------+--------------------------------+
| inet6_rlookup('2a02:f8::ffff:ffe5') | inet6_rlookup('64.128.190.61') |
+-------------------------------------+--------------------------------+
| it.watchmouse.com | ny.watchmouse.com |
+-------------------------------------+--------------------------------+
1 row in set (0.07 sec)
As you can see, inet6_lookup takes a host name and converts it to a readable IP address. The reverse lookup function, inet6_rlookup, works on both binary as well as human readable IP addresses (since v0.2).
The inet6_pton() and inet6_ntop() functions should be quite fast, but as each call to inet6_lookup() involves a DNS lookup, the lookup functions can make your queries extremely slow. Make sure you LIMIT your result set to something sensible. In general, I would not recommend to use the lookup functions in production code as I don’t know the impact of these queries on MySQL’s performance.
Once the UDF’s are installed in the MySQL plugin directory, they can be loaded at runtime using:
mysql> CREATE FUNCTION inet6_ntop RETURNS STRING SONAME "mysql_udf_ipv6.so";
mysql> CREATE FUNCTION inet6_pton RETURNS STRING SONAME "mysql_udf_ipv6.so";
mysql> CREATE FUNCTION inet6_lookup RETURNS STRING SONAME "mysql_udf_ipv6.so";
mysql> CREATE FUNCTION inet6_rlookup RETURNS STRING SONAME "mysql_udf_ipv6.so";
These functions have helped us with our immediate needs for managing IPv6 addresses in our DBMS, and hopefully they can help you too. We have some more improvements in mind, so stay tuned if you’re interested!
The current version of the UDF’s can be downloaded from:
mysql-udf-ipv6-0.2.tar.gz
Note: Compilation was tested on Debian etch+lenny, Ubuntu jaunty+karmic, and on FreeBSD. If you get it running on other platforms, send us a patch!
Pieter Ennes
WatchMouse
Posted by Pieter Ennes on September 8th, 2009
Which hosters are running IPv6, and what monitoring tools are needed? We are trying to find out!
With a bit of a delay we want to share the results of a poll we held among the hosting providers of our monitoring network in the beginning of 2008. We asked them whether they could offer native IPv6 to our stations, and if not, when they could.
The results were interesting, as none of them could at that time deliver native v6 traffic right down to our stations, and only two were up for a joint experiment with us. Very few responded that they had IPv6 on the roadmap at all; the rest indicating that they had not thought about it yet. Two responded that they were in fact waiting on some IPv6 address space from APNIC. Assuming that our selection of (at that time 25) providers is representative for hosters in general, pioneers are still in bad shape if they depend on upstream network infrastructure.
So what has changed since then? The AMS-IX IPv6 bandwidth charts for 2009 show that there has only been a minor increase in v6 traffic recently. You can also see that IPv6 traffic still accounts for only a tiny 0.2% of the total traffic volume. We will conduct a second poll now to see if matters have changed, although the above statistics are pessimistic. I will update this blog with a more detailed comparison study when we have new results.
With respect to WatchMouse, we think early adopters should have at least access to tools to monitor all the aspects of their systems during their transition to IPv6. We therefore are currently aggressively making our own infrastructure IPv6-ready to offer IPv6 monitoring as good as we can. For locations where we find no support from our upstream providers, we will be using v4 tunnels through HE, SixXS and other providers. Besides that, our developers are currently testing the necessary code changes for full IPv6 deployment.
Some of the things we are working on right now:
- Finalizing deployment of a IPv6 capable monitoring network using tunnel brokers
- Make our core systems, databases and checker software ready for IPv6
- Conduct a second poll amongst our hosters to verify the current state of v6 penetration
- Make the WatchMouse website itself available on v6
We will post any interesting information regarding our progress in this blog when we have it. In the meantime, we would like to ask what kind of tools you would need from us to be able to monitor your own transition; why not leave a comment on this site!
